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Mevcut Betonarme Okul Binalarının Güçlendirilmesi Sonrasında Değişen Yapısal Performans Özelliklerinin İncelenmesi
No full textAktif deprem kuşağında olan ve yapısal stokunda yetersizlikler bulunan Türkiye'de yaşanan şiddetli depremler sonrasında özellikle yetersiz yapısal özellikler nedeniyle çok fazla can ve mal kaybı meydana gelmektedir. Yapı stokunun önemli bir kısmı betonarme olan Türkiye'de konutların haricinde toplumsal öncelikleri oldukça yüksek olan ve afetler sonrasında acil kullanılmaları gereken kamu binaları içinde aynı problem söz konusudur. İmal edilirken yeterli mühendislik hizmeti alamamış olan bazı kamu binalarının hızlı ve etkili bir şekilde güçlendirilmesi bu açıdan oldukça önemli bir konudur. Güçlendirmenin tipi yapısal özelliklere bağlı olarak değişmekle beraber her bir güçlendirme senaryosu için yapısal performansın farklı şekillerde değişeceği de aşikârdır. Tasarım aşamasında bu değişikliklerin iyi tahmin edilmesi ve yapının performansını en etkili biçimde artıracak ve buna mütekabil düşük maliyete sahip güçlendirme yöntemlerinin tercih edilmesi önemli bir mühendislik problemidir. Bu çalışma kapsamında, deprem performansının yetersiz olduğu bilinen üç farklı okul (8, 14 ve 22 derslikli) binası modeli üzerinde bir dizi analiz gerçekleştirilmiştir. Saha verileri mevcut olan binaların mevcut durumları TBDY 2018'e göre değerlendirildikten sonra yetersiz performans özellikleri değişen güçlendirme stratejileri ile (perde ilavesi, kolonların mantolanması, perde ilavesi + kolonların mantolanması) iyileştirilmiştir. Modellemelerde STA4CAD programı kullanılmıştır. Çalışmanın parametrik içeriğinde, yapıların bulunduğu iller, AFAD, Türkiye Deprem Tehlike Haritaları İnteraktif Web Uygulaması üzerinden yapı koordinatına ait en büyük yer ivmesi (PGA) değerlerine göre seçilmiştir. Bu çalışma kapsamında PGA değeri 0.295 m/s² olan Ankara/Çankaya ve PGA değeri 0.995 m/s² olan Sakarya/Adapazarı alınmıştır. Mevcut yapıların bulunduğu yerel zemin sınıfları (ZC, ZD ve ZE), yapıların mevcut donatı sınıfları (S220, S420), yapıların mevcut beton dayanımlarının (10, 15 ve 20 MPa) değişkenliği dikkate alınmıştır. Söz konusu değişkenlere göre 22 x 33 x 4 (432) adet yapı modeli üzerinden değerlendirmeler yapılmıştır. Yapılan değerlendirmelere göre perde ilavesi + mantolama tipi güçlendirmenin yapılarda periyoda en fazla etkisi olan güçlendirme türü olduğu, buna bağlı olarak spektral deplasman taleplerinde bu tür güçlendirmelerde önemli azalmalar olduğu tam tersine dayanım fazlalığı katsayısının ve güçlendirme maliyetinin de bu tür güçledirmelerde diğer güçlendirme türlerine göre daha fazla artış gösterdiği görülmüştür. Güçlendirilmiş binalar için TBDY 2018 de dayanım fazlalığı hedefinin olmaması önemli bir eksilik olduğu ve bunun yeni yönetmeliklerde dikkate alınması gereken bir faktör olacağı görülmüştür.In Turkey, which is located in an active seismic zone and has structural deficiencies in its building stock, severe earthquakes have resulted in significant loss of life and property, especially due to inadequate structural features. In Turkey, where a significant portion of the building stock is reinforced concrete, the same problem is encountered not only in residential buildings but also in public buildings, which have high social priorities and must be urgently used after disasters. The rapid and effective strengthening of some public buildings, which did not receive adequate engineering services during their construction, is a very important issue from this perspective. Although the type of strengthening depends on structural characteristics, it is evident that structural performance will change in different ways for each strengthening scenario. During the design phase, predicting these changes accurately and selecting strengthening methods that will increase the building's performance most effectively and, correspondingly, have low costs is an important engineering problem. In this study, a series of analyses have been performed on three different school building models (with 8, 14, and 22 classrooms) known to have inadequate earthquake performance. After evaluating the current conditions of the buildings with available site data according to TBDY 2018, their inadequate performance characteristics have been improved using different strengthening strategies (addition of shear walls, jacketing of columns, addition of shear walls + jacketing of columns). The STA4CAD program have been used for modeling. In the parametric content of the study, the cities where the buildings are located, AFAD, and the Turkey Earthquake Hazard Map Interactive Web Application were used to select the maximum ground acceleration (PGA) values for the building coordinates. In this study, Ankara/Çankaya with a PGA value of 0.295 m/s² and Sakarya/Adapazarı with a PGA value of 0.995 m/s² were chosen. The local soil classes (ZC, ZD, and ZE) of the existing buildings, the reinforcement classes (S220, S420), and the variability of the concrete strengths of the buildings (10, 15, and 20 MPa) have been considered. Evaluations have been based on 22 x 33 x 4 (432) building models according to these variables. The evaluations indicate that the shear wall addition + jacketing -type strengthening method has the most significant effect on the structural period. Consequently, spectral displacement demands decrease considerably with this type of strengthening. However, the over strength factor and reinforcement costs are noticeably higher compared to other strengthening methods. The absence of a over strength factor target in TBDY 2018 for reinforced buildings is seen as a major deficiency, which should be considered in future regulations
Robust, Explainable, and Statistically Validated Gastrointestinal Image Analysis Using Modern Deep Learning Architectures
No full textDeep learning models achieve high accuracy in medical image classification. However, their clinical adoption faces two major problems. Insufficient robustness evaluation under realistic degradation conditions is one issue. Lack of proper interpretability mechanisms is another. Such limitations critically hinder their use in clinical settings. The critical shortcomings are particularly pronounced in gastrointestinal endoscopic diagnosis, where image quality varies substantially and clinical decision-making demands transparent, explainable artificial intelligence systems. To address such research gaps, this study presents a comprehensive framework that systematically evaluates Base and Tiny variants of three modern architectures (Vision Transformer, Swin Transformer, ConvNeXt) for gastrointestinal abnormality classification. Unlike previous studies focused exclusively on clean data, this evaluation incorporates realistic perturbations including Gaussian noise, blur, rotation, color jitter, CutMix, and MixUp, combined with McNemar's statistical significance testing and Local Interpretable Model-agnostic Explanations for clinical interpretability. The experimental results reveal distinct performance patterns across different conditions. Among all tested variants, ConvNeXt_Tiny achieved the highest performances (98.50% accuracy, 98.46% F1-Score and 99.11% AUC) under clean conditions. When evaluated under degraded conditions, ConvNeXt_Tiny showed strong resilience to low-level degradations, while Swin_Tiny demonstrated superior robustness to geometric and photometric distortions. Statistical validation confirmed significant performance differences under distortions, and explainability analysis revealed that high-performing models consistently focused on clinically meaningful regions. These findings provide evidence-based guidance for clinical deployment where reliability under varied conditions and transparent explainability represent paramount considerations for successful healthcare integration
Özel Hastanelerde Mekan Analizi ve Kullanıcı Memnuniyeti Üzerine Bir Çalışma: 'Özel Konya Farabi Hastanesi' Örneği
No full textGünümüzde gelişen teknoloji ve sosyoekonomik durumun değişmesi ile hastanelere başvuran kişilerin fiziki ve psikolojik anlamda beklentileri artmaktadır. Buna paralel olarak özellikle özel hastanelerde, tasarım kriterlerinin değişmesinden ve pozitif anlamda iyileşmeden söz edilebilir. Bu çalışmada, özel hastanelerde bulunan, yönetmeliklerde ölçüleri belirlenmiş mekanların fiziksel ve psikolojik olarak yeterli olup olmadığı araştırılmış, sağlık çalışanları kapsamında konfor beklentileri incelenmiştir. Konya ili Selçuklu ilçesinde bulunan Özel Konya Farabi Hastanesi'nin mekân analizleri yapılarak, özel hastanelerde bulunması gereken mekanların tasarım anlamında günümüz konfor beklentilerinin, sağlık çalışanları üzerinde yapılan anket çalışması ile memnuniyet düzeyleri araştırılmıştır.Today, with the developing technology and changing socioeconomic status, the physical and psychological expectations of people applying to hospitals are increasing. In parallel with this, it can be said that design criteria have changed and positive improvements have been made, especially in private hospitals. In this study, it was investigated whether the spaces in private hospitals, whose dimensions are determined in the regulations, are physically and psychologically sufficient, and the comfort expectations of healthcare workers were examined. The space analysis of Private Konya Farabi Hospital, located in Selçuklu district of Konya province, was conducted, and the comfort expectations of today in terms of design of the spaces that should be in private hospitals, and the satisfaction levels of healthcare workers were investigated with a survey study conducted on them
Ultrahigh Antibacterial Response and Biochemical Activity in Mg-Sn-HA Material Systems
No full textGunes, Eda/0000-0001-7422-9375The effects of metallic tin(Sn) and hydroxyapatite(HA) ceramic particles on metallic magnesium's mechanical properties and antibacterial (S.aureus) response along with bioactivity (toxicity) against D.melanogaster larvae, including the impact on survival, development, sex, longevity, were studied. Three different variations of self-assembled Mg-based materials were synthesized by mechanical alloying and densification of the samples was accomplished by hot press sintering. SEM analysis reveals that the smallest particle morphology was obtained in the Mg-3Sn alloy wherein excessive plastic deformation resulted in a monodisperse particle distribution, enabling uniform distribution of reinforcing elements. The most significant gain in mechanical properties was observed in the Mg-Sn system in which the formation of the Mg2Sn intermetallic results Brinell hardness of 184, corresponding similar to 500 % increase relative to pure Mg. The intermetallic Mg2Sn phase and its high-volume fraction in the Mg matrix leads hardening by the Orowan mechanism. In all treatment groups, the overall survival rate is >= 80 %, which shows that the produced alloys and composites are not neither toxic nor lethal to the model organisms. According to the survival rate and development time data, it was determined that the sex of the organisms shifted in favor of the first group (males) and the second group (females), while the oxidative stress (OSI) increased in organisms in contact with the first group (males). The Mg-HA and Mg-Sn-HA systems exhibit superb antibacterial properties, showing complete inhibition of S.aureus after 24-h incubation period. Overall, such alloys could have a significant impact on a range of clinical and biomedical applications because of their outstanding antibacterial properties as demonstrated in this study.The financial support provided by the Scientific Research Projects Coordination Unit (SRPCU) of Selcuk University through contract# 18401032, and the Scientific Research Projects at Konya Technical University through contract# 191019035 is gratefully acknowledged.Scientific Research Projects Coordination Unit (SRPCU) of Selcuk University [18401032]; Scientific Research Projects at Konya Technical University [191019035
Production of Piezoelectric Aerogel Materials, Increasing Efficiency in Energy Harvesting
No full textIn this study, aerogel composite materials with piezoelectric properties were synthesised and their performances in energy harvesting applications were investigated in detail. Within the scope of the research, polyvinyl alcohol (PVA)-based, medium conductive and thermally resistant polybenzimidazole (PBI) and piezoceramic material (barium calcium titanate zirconate (BCZT) and zinc oxide (ZnO)) doped composite aerogels were prepared. The obtained piezoaerogel was dried at 50 bar and 120 °C by critical carbon dioxide drying method and three-dimensional macroporous structures were preserved. Surface morphological properties and macroporosity distribution graph of composite aerogels were analysed by FESEM. Energy harvesting was increased by pressing the obtained piezoaerogel samples at 60 °C. As a result of FTIR and TGA analyses performed to investigate the structural properties of aerogels, it was determined that PBI doping increased the thermal resistance and all three aerogels were completely degraded at a temperature of approximately 480 °C. The output voltages generated as a result of mechanical impacts applied to the material were recorded and analysed by oscilloscope. According to the results of the study, a significant increase in piezoelectric performance was observed by using BCZT and ZnO dopants in the range of 1%-3%. In samples with 2 cm² surface area, a maximum output voltage of 19.0 V was obtained as a result of the force applied by finger pressure. In addition, the output power density and current value produced by the piezoaerogel were determined by measurements made by the two-probe method. The maximum output power was measured as 1,280x10-3 W for 0.95 mm thick piezoaerogel material. 3% BCZT doped sample was found to have the highest output power.Bu çalışmada, piezoelektrik özelliklere sahip aerojel kompozit malzemelerin sentezi gerçekleştirilmiş ve bu malzemelerin enerji hasadı uygulamalarındaki performansları detaylı bir şekilde incelendi. Araştırma kapsamında, polivinil alkol (PVA)temelli olmak üzere orta iletken ve termal dayanımlı polibenzimidazol (PBI) ve piezoseramik malzeme(baryum kalsiyum titanat zirkonat (BCZT) ve çinko oksit (ZnO)) katkılı kompozit aerojeller hazırlandı. Elde edilen piezoaerojel, kritik karbondioksit kurutma yöntemi ile 50 bar ve 120 °C'de kurutularak ve üç boyutlu makro gözenekli yapıların korunması sağlandı. Kompozit aerojellerin yüzey morfolojik özellikleri ve makro gözeneklilik dağılım grafiği FESEM ile analiz edilmiştir. Elde edilen piezoaerojel örneklerine 60 °C'de presleme işlemi uygulanarak enerji hasadı artırılmıştır. Aerojellerin yapısal özelliklerinin incelenmesi amacıyla gerçekleştirilen FTIR ve TGA analizleri sonucunda, PBI katkısının termal dayanımı artırdığı ve her üç aerojelin de yaklaşık 480 °C sıcaklıkta tamamen bozunduğu belirlendi. Malzemeye uygulanan mekanik darbeler sonucunda oluşan çıkış gerilimleri osiloskop aracılığıyla kaydedilmiş ve analiz edilmiştir. Çalışma sonuçlarına göre, BCZT ve ZnO katkılarının %1–%3 aralığın dakullanılmasıyla piezoelektrik performansta anlamlı bir artış gözlendi. 2 cm² yüzey alanına sahip numunelerde, parmak basıncıyla uygulanan kuvvet sonucunda maksimum 19.0 V çıkış gerilimi elde edildi. Ayrıca, Two-prob yöntemiyle yapılan ölçümlerle piezoaerojelin ürettiği çıkış güç yoğunluğu ve akım değeri belirlendi. Maksimum çıkış gücü 0.95 mm kalınlıktaki piezoaerojel malzeme için 1,280x10-3 W olarak ölçülmüştür. En yüksek çıkış gücünün%3 BCZT katkılı numuneye ait olduğu görüldü
Measurement of the Inclusive Tt¯ Cross Section in Final States with at least One Lepton and Additional Jets with 302 Pb−1 of Pp Collisions at S = 5.02 TeV
No full textA measurement of the top quark pair (tt¯) production cross section in proton-proton collisions at a centre-of-mass energy of 5.02 TeV is presented. The data were collected at the LHC in autumn 2017, in dedicated runs with low-energy and low-intensity conditions with respect to the default configuration, and correspond to an integrated luminosity of 302 pb−1. The measurement is performed using events with one electron or muon, and multiple jets, at least one of them being identified as originating from a b quark (b tagged). Events are classified based on the number of all reconstructed jets and of b-tagged jets. Multivariate analysis techniques are used to enhance the separation between the signal and backgrounds. The measured cross section is 62.5±1.6stat−2.5+2.6syst±1.2lumi pb. A combination with the result in the dilepton channel based on the same data set yields a value of 62.3 ± 1.5 (stat) ± 2.4 (syst) ± 1.2 (lumi) pb, to be compared with the standard model prediction of 69.5−3.7+3.5 pb at next-to-next-to-leading order in perturbative quantum chromodynamics. © 2025 Elsevier B.V., All rights reserved
Multi-Objective Task Planning for Multi-UAVs Based on Constraint Satisfaction Problem
No full textMulti-task planning for Unmanned Aerial Vehicles (UAVs) presents a complex optimization challenge, requiring the harmonization of tasks with dynamic capabilities such as sensor capacity, location, fuel, and payload. This study extends the conventional Constraint Satisfaction Problem (CSP) model by incorporating a temporal dimension, introducing the Temporal CSP (TCSP) framework. TCSP associates UAV capabilities with static and dynamic constraints by structuring task pairs within sequential time windows. However, the greedy nature of TCSP imposes inherent limitations in terms of cost efficiency and operational effectiveness. To address these limitations, the proposed Improved Temporal Constraint Satisfaction Problem (ITCSP) introduces two key innovations: (1) a dynamic decision-making mechanism that selects the optimal UAV for a task domain while evaluating its potential to complete subsequent tasks in-flight, and (2) a hybrid control method that reduces takeoff-landing cycles by optimizing time and fuel costs. This enables UAVs to perform missions seamlessly without intermediate landings. The framework was validated through a two-phase experimental design. In the first phase, simulations using synthetic data-inspired by real-world scenarios-assigned UAVs with heterogeneous capabilities to diverse mission requirements. The second phase employed dynamic programming to update temporal windows for task pairs, while comparing the performance of node consistency, backtracking, and arc consistency methods. Results demonstrated that ITCSP achieved 12 times fewer takeoff-landing cycles than TCSP in a 64-task scenario, significantly reducing fuel and time costs. Even in an 8-task scenario, ITCSP produced more optimized solutions with comparable time complexity. These findings underscore ITCSP's superiority in multi-task planning, emphasizing its potential to enhance resource efficiency and operational sustainability in UAV deployments
A Comparative Study on Experimental and FEA-Based Simulation of Dry Sliding Wear Behavior of Boronized AISI 304 Stainless Steel at Elevated Temperatures
No full textIn this study, the influence of boronizing on the high-temperature wear behavior of AISI 304 was examined experimentally and with FEA simulation. Boronizing, conducted at 950 degrees C for 3 h using the powder-pack boronizing technique, showed an approximately 7-fold increase in hardness compared to untreated sample. Boride layer characterization was performed using XRD, SEM, and EDS line analyses. Wear tests were performed at ambient temperatures of 25, 250, and 500 degrees C. While the wear rates of the untreated sample increased dramatically with increasing temperature, those of the boronized samples were significantly limited. FEA simulation using the Johnson-Cook fracture model demonstrated a high degree of consistency with the experimental wear profiles and this alignment enables reliable wear predictions. The oxide layer formation was observed on the worn surface of boronized samples during the tests at elevated temperatures, resulting in less plastic deformation.This study was supported by TUBITAK (Turkish Scientific and Technological Research Council) with project no. 221M417.TUBITAK (Turkish Scientific and Technological Research Council) [221M417
Two-Echelon Location Selection and Unmanned Aerial Vehicle- Assisted Vehicle Routing Problem
No full textIn recent years, the potential use of Unmanned Aerial Vehicle (UAV) technology in logistics processes and the rapid developments in this field have made UAV-assisted routing problems an important research topic. In this paper, we consider a two-echelon location selection and UAV-assisted vehicle routing problem. In this problem, trucks leave from the main depot with their packages and UAVs, move through potential service points (mobile depot), and return to the main depot. At each mobile depot, UAVs are launched from the truck to service the customers, and the trucks wait for the UAVs to complete their service and return. The UAVs are capable of making multiple trips between the mobile depot and customers, carrying only one package at a time. The objective is to minimize the maximum tour time. In this paper, a new problem, which involves a multi-truck structure and multiple launches of UAVs from a mobile depot, is investigated for the first time to the best of our knowledge in the literature. A mixed integer linear programming model is proposed to solve the problem. In order to evaluate the performance of the proposed mathematical model, the number of trucks is determined as one and two, experimental analyses are performed and the results are reported in detail
