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Analytical Investigation of Lateral-Torsional Buckling of Tapered Cantilevers With I-Section
No full textI-section steel profiles are commonly used as cantilever beams in steel structures. They are loaded to resist bending about their strong axes for efficient material utilisation. When subjected to bending along the strong axis, I-section cantilevers experience out-of-plane lateral deformation and torsion at a certain critical load, leading to a loss of stability. This failure mode is known as lateral-torsional buckling. This global stability loss, which may occur before yielding the cross-section, should be considered in structural design. The lateral-torsional buckling behaviour of slender columns, beams, cantilevers, and axially loaded beams has been extensively investigated in the literature via analytical, numerical, and experimental methods. Compared to simply supported beams, the lateral-torsional buckling mode of cantilever beams is more complex, often making the derivation of closed-form solutions impractical and requiring numerical approaches. This study developed an analytical procedure based on the energy method to calculate the lateral-torsional buckling loads of web and/or flanges tapered cantilevers with symmetric I-section. The proposed analytical method considers all influential factors, including the tapering levels of the flange and/or web, slenderness, transverse load type, and the position of the transverse load on the cross-section. The analytical solutions have been validated using finite element analyses with one-dimensional (1D) beam elements incorporating warping effects. The lateral-torsional buckling behaviour of webs and/or flanges tapered cantilevers with symmetric I-sections has been thoroughly examined and interpreted in detail.I kesitli çelik profiller, çelik yapılarda konsol kiriş olarak sıklıkla kullanılır. Malzemeyi ekonomik kullanmak adına eğilme etkilerini güçlü eksenleri ile karşılayacak şekilde yüklenirler. Güçlü ekseninde eğilen I-kesitli konsol, belirli bir limit yük değerinde düzlem dışı yanal deformasyon ve burulma sergileyerek uğradıkları stabilite kaybı yaşar. Bu göçme modu yanal burulmalı burkulma olarak adlandırılır. Kesitte akma öncesi gerçekleşebilecek bu global stabilite kaybının tasarımda dikkate alınması gerekir. Literatürde narin kolon, kiriş, konsol ve eksenel yüklü kirişlerin yanal burulmalı burkulması analitik, nümerik ve deneysel olarak araştırılmıştır. Basit kirişlerden farklı olarak konsol kirişlerin yanal burulmalı burkulma modu daha karmaşıktır, kapalı formda bir denklem elde etmek mümkün olmayabilir ve genellikle sayısal çözüm gerektirir. Çalışma kapsamında gövdesi ve/veya başlığı daralan simetrik I-kesitli konsolların yanal burulmalı burkulma yüklerini hesaplamak için enerji yöntemine dayalı analitik bir prosedür geliştirilmiştir. Sunulan analitik yöntem, başlık ve/veya gövde daralma seviyesi, narinlik, enine yük tipi, enine yükün en kesit üzerinde pozisyonu etkilerinin tamamını göz önüne almaktadır. Analitik çözümler, çarpılma etkilerini hesaba katan bir boyutlu (1B) çubuk elemanların kullanıldığı sonlu eleman analizleri ile doğrulanmıştır. Gövdesi ve/veya başlığı daralan simetrik I-kesitli konsolların yanal burulmalı burkulma davranışları detaylı olarak incelenmiş ve yorumlanmıştır
Performance Analysis of Cloud Computing Task Scheduling Using Metaheuristic Algorithms in DdoS and Normal Environments
No full textCloud computing has emerged as a fundamental pillar of modern technology, enabling large-scale data management, computational efficiency, and operational flexibility. However, critical challenges persist, particularly concerning security and performance. DDoS attacks severely impact cloud infrastructure by degrading system performance and causing service disruptions. These persistent threats raise concerns about cloud system reliability and underscore the necessity for advanced security measures. This study investigates the cloud computing task scheduling problem, recognized as NP-hard, and explores the impact of adversarial conditions such as DDoS attacks on system performance. To address this challenge, metaheuristic algorithms are employed. The research evaluates the effectiveness of traditional approaches, including genetic algorithms (GAs), particle swarm optimization (PSO), and artificial bee colony (ABC), while also introducing a GA–PSO algorithm designed to enhance task scheduling efficiency. The proposed method aims to minimize makespan by optimizing task allocation across virtual machines (VMs) within cloud environments. A comparative analysis of scheduling performance under both normal and DDoS-affected conditions reveals that metaheuristic techniques contribute significantly to system resilience. Furthermore, the GA–PSO algorithm demonstrates notable improvements at specific iteration levels. The findings underscore the potential of advanced scheduling methods to enhance cloud computing sustainability while offering practical solutions to mitigate real-world security threats. © 2025 by the authors
Measurement of the Double-Differential Inclusive Jet Cross Section in Proton-Proton Collisions at √s=5.02 TeV
No full textSarkar, Uttiya/0000-0002-9892-4601; Tornago, Marta/0000-0001-6768-1056;The inclusive jet cross section is measured as a function of jet transverse momentum p(T) and rapidity y. The measurement is performed using proton-proton collision data at root s = 5.02 TeV, recorded by the CMS experiment at the LHC, corresponding to an integrated luminosity of 27.4 pb(-1). The jets are reconstructed with the anti-k(T) algorithm using a distance parameter of R = 0.4, within the rapidity interval |y| 2, and across the kinematic range 0.06 p(T) 1 TeV. The jet cross section is unfolded from detector to particle level using the determined jet response and resolution. The results are compared to predictions of perturbative quantum chromodynamics, calculated at both next-to-leading order and next-to-next-to-leading order. The predictions are corrected for nonperturbative effects, and presented for a variety of parton distribution functions and choices of the renormalization/factorization scales and the strong coupling alpha(S).Marie-Curie program (European Union); European Research Council (European Union); Horizon 2020 Grant (European Union) [675440, 724704, 752730, 758316, 765710, 824093]; COST Action (European Union) [CA16108]; Leventis Foundation; Alfred P. Sloan Foundation; Alexander von Humboldt Foundation; Science Committee(Armenia) [22rl-037]; Belgian Federal Science Policy Office; Fonds pour la Formation a la Recherche dans l'Industrie et dans l'Agriculture (FRIA-Belgium); Agentschap voor Innovatie door Wetenschap en Technologie (IWT-Belgium); FWO (Belgium) under the "Excellence of Science - EOS" - be.h project [30820817]; Beijing Municipal Science AMP; Technology Commission [Z191100007219010]; Fundamental Research Funds for the Central Universities (China); Ministry of Education, Youth and Sports (MEYS) of the Czech Republic; Shota Rustaveli National Science Foundation (Georgia) [FR-22-985]; Deutsche Forschungsgemeinschaft (DFG), under Germany's Excellence Strategy [EXC 2121, 390833306, 400140256 - GRK2497]; Hellenic Foundation for Research and Innovation (HFRI) (Greece) [2288]; Hungarian Academy of Sciences; Council of Science and Industrial Research, India; Latvian Council of Science; Ministry of Education and Science [2022/WK/14]; National Science Center (Poland) [Opus 2021/41/B/ST2/01369, 2021/43/B/ST2/01552]; Fundacao para a Ciencia e a Tecnologia (Portugal) [CEECIND/01334/2018]; National Priorities Research Program by Qatar National Research Fund; ERDF "a way of making Europe"; Programa Estatal de Fomento de la Investigacion Cientifica y Tecnica de Excelencia Maria de Maeztu [MDM-2017-0765]; Programa Severo Ochoa del Principado de Asturias (Spain); Chulalongkorn Academic into Its 2nd Century Project Advancement Project; National Science, Research and Innovation Fund via the Program Management Unit for Human Resources AMP; Institutional Development, Research and Innovation (Thailand) [B37G660013]; Kavli Foundation; Nvidia Corporation; SuperMicro Corporation; Welch Foundation [C-1845]; Weston Havens Foundation (U.S.A.); F.R.S.-FNRS; New National Excellence Program - UNKP; NKFIH research grants (Hungary) [K 124845, K 124850, K 128713, K 128786, K 129058, K 131991, K 133046, K 138136, K 143460, K 143477, 2020-2.2.1-ED-2021-00181, TKP2021-NKTA-64]; ICSC - National Research Center for High Performance Computing, Big Data and Quantum Computing - EU NexGeneration program (Italy); MCIN/AEIIndividuals have received support from the Marie-Curie program and the European Research Council and Horizon 2020 Grant, contract Nos. 675440, 724704, 752730, 758316, 765710, 824093, and COST Action CA16108 (European Union); the Leventis Foundation; the Alfred P. Sloan Foundation; the Alexander von Humboldt Foundation; the Science Committee, project no. 22rl-037 (Armenia); the Belgian Federal Science Policy Office; the Fonds pour la Formation a la Recherche dans l'Industrie et dans l'Agriculture (FRIA-Belgium); the Agentschap voor Innovatie door Wetenschap en Technologie (IWT-Belgium); the F.R.S.-FNRS and FWO (Belgium) under the "Excellence of Science - EOS" - be.h project n. 30820817; the Beijing Municipal Science ; Technology Commission, No. Z191100007219010 and Fundamental Research Funds for the Central Universities (China); the Ministry of Education, Youth and Sports (MEYS) of the Czech Republic; the Shota Rustaveli National Science Foundation, grant FR-22-985 (Georgia); the Deutsche Forschungsgemeinschaft (DFG), under Germany's Excellence Strategy - EXC 2121 "Quantum Universe" - 390833306, and under project number 400140256 - GRK2497; the Hellenic Foundation for Research and Innovation (HFRI), Project Number 2288 (Greece); the Hungarian Academy of Sciences, the New National Excellence Program - UNKP, the NKFIH research grants K 124845, K 124850, K 128713, K 128786, K 129058, K 131991, K 133046, K 138136, K 143460, K 143477, 2020-2.2.1-ED-2021-00181, and TKP2021-NKTA-64 (Hungary); the Council of Science and Industrial Research, India; ICSC - National Research Center for High Performance Computing, Big Data and Quantum Computing, funded by the EU NexGeneration program (Italy); the Latvian Council of Science; the Ministry of Education and Science, project no. 2022/WK/14, and the National Science Center, contracts Opus 2021/41/B/ST2/01369 and 2021/43/B/ST2/01552 (Poland); the Fundacao para a Ciencia e a Tecnologia, grant CEECIND/01334/2018 (Portugal); the National Priorities Research Program by Qatar National Research Fund; MCIN/AEI/10.13039/501100011033, ERDF "a way of making Europe", and the Programa Estatal de Fomento de la Investigacion Cientifica y Tecnica de Excelencia Maria de Maeztu, grant MDM-2017-0765 and Programa Severo Ochoa del Principado de Asturias (Spain); the Chulalongkorn Academic into Its 2nd Century Project Advancement Project, and the National Science, Research and Innovation Fund via the Program Management Unit for Human Resources ; Institutional Development, Research and Innovation, grant B37G660013 (Thailand); the Kavli Foundation; the Nvidia Corporation; the SuperMicro Corporation; the Welch Foundation, contract C-1845; and the Weston Havens Foundation (U.S.A.)
Fındık Atıklarından Hidrokömür Üretimi ve Pb (ıı) ve Cr (ııı) Gideriminde Kullanımı
No full textAğır metaller çevreye ve canlı organizmalara her geçen gün daha çok zarar vermektedir. Bu tür kirleticileri ortadan kaldırmak veya azaltmak için çok sayıda çalışma yapılmıştır ve yapılmaya da devam etmektedir. Bu çalışmada fındık atığından (HW) hidrokömür üretilmiş ve üretilen bu adsorbanla Pb ve Cr iyonlarının giderim çalışmaları yapılmıştır. Bu şekilde hem HW'nin değerlendirilmesi sağlanmış hem de çevre için çok zararlı olan ağır metallerin giderimi sağlanmıştır. Üretilen hidrokömürlerin yapısal ve morfolojik özellikleri TGA, DSC, FE-SEM, FT-IR ve EDX analizleri ile karakterize edilmiştir. Başlangıç konsantrasyonu, sıcaklık, adsorban dozajları, temas süresi ve pH gibi birçok parametrenin adsorpsiyon üzerindeki etkileri tartışılmıştır. Farklı parametre ortamlarında yapılan çalışmalarda hidrokömürün, Pb ve Cr iyonlarının sırasıyla %76'sını ve %67'sini giderdiği belirlenmiştir. Ayrıca, üretilen hidrokömürün adsorpsiyon sistemini daha iyi anlamak için Langmuir ve Freundlich izoterm modelleri, pseudo-birinci mertebe ve pseudo-ikinci mertebe kinetik modelleri ve Gibbs serbest enerjisi gibi termodinamik parametreler araştırıldı. Ayrıca, hidrokömürün bir adsorban olarak yeniden kullanılabilirliği araştırıldı ve malzemenin dört döngüden sonra bile etkili bir şekilde çalışmaya devam ettiği gözlemlendi
A Novel Architecture Based on a Pyrrole-Functionalized Dithieno[3,2-B:2′,3′ (dtp)-Type Conducting Polymer and Thiol-Modified Calixarene Derivative for Biophotovoltaic Solar Cells: Photocurrent and Hydrogen Generations Via Both Photosynthesis and Respiratory System
No full textThis review explores the potential of biophotovoltaic devices (BPVs) as a sustainable solution for addressing the global energy crisis and combating climate change. BPVs generate renewable electricity from sunlight and water through the photosynthetic activity of microorganisms such as cyanobacteria and algae, which act as living photocatalysts. The study essentially focuses on improving photocurrent outputs through developing efficient anode materials. An innovative photoanode design is introduced employing cyanobacteria immobilized on a P(DTP-Ph-Pyr)/Calixarene-AuNP-modified surface. This design features a porous structure conducive to cyanobacterial attachment and efficient electron transfer. As a first step, the conductive polymeric film of 4-(4-(1H-pyrrol-1-yl)phenyl)-4H-dithieno[3,2-b:2 ',3 '-d]pyrrole (DTP-Ph-Pyr) monomer was coated onto a gold electrode via electropolymerization method. Then, a mixture of thiol- and carboxylic group-modified calixarene and gold nanoparticles (AuNPs) was applied to enhance the photoelectrode's performance. The surface of the modified electrode enabled the successful immobilization of Leptolyngbya sp. cyanobacterial cells, providing a reliable interface for efficient photocurrent and hydrogen generation. Calixarenes and their derivatives act as favorable agents for cyanobacterial immobilization due to their specific configurations. Moreover, the formation of covalent bonds between the carboxyl groups of calixarenes and the amino groups in cyanobacteria facilitates the robust immobilization of cyanobacterial cells while maintaining their well-ordered structural integrity and organized cellular architecture. A complementary cathode structure, employing aniline-modified Pt nanoparticles, facilitates the reduction of protons to generate hydrogen gas. Overall, this study underscores the promise of BPVs as feasible clean energy technologies and introduces innovative methods to improve their efficiency and sustainability.The authors would like to acknowledge Konya Technical University, KTO Karatay University, and Istanbul University for their support.Konya Technical University, KTO Karatay University; Istanbul Universit
Pre-Alpine Illitization Ages From the Palaeozoic Sequences of the Tauride Belt, Southern Turkiye: New Data for a Late Palaeozoic Event in Northern Gondwana
No full textUysal, Ibrahim Tonguc/0000-0002-8263-8774Due to the effects of the Alpine orogeny, it is extremely difficult to obtain age data for pre-Alpine geological events for northern Gondwana. This study aims to study the metamorphism in Precambrian (Ediacaran) metaclastic rocks of the Geyik Dagi unit and re-evaluate the geodynamic models of the northern Gondwana-margin based on the geochronology of illite diagenesis in the Late Silurian to Carboniferous shales of the Aladag and Geyik Dagi units of the Taurides, in southern Turkiye. The average illitization (diagenesis) ages of similar to 275 Ma and similar to 165 Ma correspond to the periods of main unconformities between the Middle Carboniferous and the Late Permian and the Triassic and the Late Jurassic. The fossil records from below and above the unconformity plane between the Middle Carboniferous and the Late Permian indicate a gap of > 70 Ma. Mineralogical and organic matter reflectance data indicate a temperature difference of similar to 50 degrees C between Permian and Carboniferous units indicating different thermal gradients below and above the hiatus. This thermal event coincides with the maximum burial depth resulting from the Palaeozoic subsidence curve of the Geyik Dagi Unit. Mineral and organic petrography-based thermal indicators indicate a pre-Alpine (Variscan) regional tectonic event, confirmed here for the first time by combined mineralogical, organic-petrographic, and isotopic age data. The new data may have the potential to re-evaluate geodynamic models of the northern Gondwana-margin during the Late Palaeozoic. The illitization ages associated with the Alpine metamorphism are ascribed to ophiolite emplacement during the Cretaceous and to tectonic events during the Eocene compressional period, which led to the present nappe structure of the Taurides.Radiometric dating was partly funded through a grant from the Queensland State Government allocated to the Queensland Geothermal Energy Centre of Excellence (QGECE). Support by Hal Gurgenci (former QGECE's director) is particularly acknowledged. We thank Yue-xing Feng and Ai Duc Nguyen (University of Queensland, Australia) for their help with analytical work and technical assistance to perform Rb-Sr analyses. We also thank to Editor-in-Chief Prof. Dr. Robert Stern, Dr. Mathias Hueck and two anonymous reviewers for their valuable contributions to the improving of the manuscript and for their constructive suggestions.Scientific and Technological Research Council of Trkiye; Queensland State Government; Queensland Geothermal Energy Centre of Excellence (QGECE
Adsorption-Assisted Photocatalytic Degradation of Anionic Direct Yellow-50 and Cationic Methylene Blue Dyes by Chemically Synthesized Poly(1,5-Diaminoanthraquinone
No full textConducting polymers renowned for their exceptional photocatalytic activity, conductivity, and visible-light absorption capabilities present a compelling alternative for advanced photocatalytic applications. In this regard, the creation of conductive polymers of the next generation has enormous promise for improving energy efficiency as well as solving environmental issues. In this study, the conductive polymer poly(1,5-diaminoanthraquinone) (PDAAQ) with a band gap of 1.28 eV and an electrical conductivity of 1.23 S/cm was successfully synthesized via chemical oxidative polymerization using ammonium peroxydisulfate as an oxidant and perchloric acid as an initiator in an acetonitrile polymerization medium. The adsorption-assisted photocatalytic performance of PDAAQ has been investigated in cationic methylene blue (MB) and an anionic direct yellow (DY) dye under visible irradiation. The effect of polymerization medium, oxidant type, polymerization time, and monomer oxidant ratio on adsorption-assisted photocatalytic degradation of MB was investigated. The synthesized PDAAQ polymer demonstrates exceptional photocatalytic performance, completely degrading MB and DYE dyes under visible light illumination in 6 and 8 min through an adsorption-assisted photocatalysis mechanism. Besides, the photocatalytic dye degradation performance of PDAAQ was investigated for the degradation of synthetic wastewater (SWW) under visible light. The PDAAQ polymer proves to be an effective photocatalyst for photocatalytic applications, showcasing exceptional potential in degrading model dyes and treating synthetic wastewater. © The Author(s) 2025.Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, TÜBİTAK, (221M523, 201116020, 232316064
Determination of Temperature Effects on Cortical Bone Milling Using Taguchi Method
No full textIn medical applications, minimizing thermal damage to biological tissue is of utmost importance for cell viability. In this experimental study, the effects of processing parameters on temperature variation during milling of cortical bone were investigated. Using the Taguchi method, optimization of parameters was performed to identify combinations that minimize the thermal rise, thus reducing the risk of necrosis and at the same time preserving bone viability. The effect of cutting tool rotational speed, feed rate, depth of cut and tool geometry on temperature changes in cortical bone samples was analyzed. Bovine femoral cortical bone samples were subjected to controlled milling trials in which temperature changes near the cutting interface were recorded in real time using a camera with a sensitive thermal sensor. Analysis of variance (ANOVA) was used to determine the statistical significance of the effect of parameters on temperature rise. The findings of the study show that there are significant interactions between the machining parameters affecting the thermal response. Statistical analysis showed that the depth of cut was the most important factor on cortical bone processing temperature, contributing 52.1% in reducing temperature values. It is followed by the number of cutting tool teeth with 23.77% and rotational speed with 18.59%. The optimal machining conditions that minimize thermal damage identified by the study provide effective baseline information for safer and more efficient bone milling procedures. © The Author(s) 2025.Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, TÜBİTAK; Selçuk Üniversitesi, SÜ, (22111001); Selçuk Üniversitesi, S
MA-OFDM a New Multiple Access Technique for 3GPP-Defined Redcap IoT Devices
No full textRedCap devices face challenges related to efficient multiple access techniques that can fully leverage their potential while adhering to their constraints. There are many multiple access techniques proposed in the literature recently, but none of them is deemed a good fit for the multi-facet requirements of RedCap devices. Motivated by that, this paper introduces a new multiple-access technique designed to address these challenges, aiming to optimize the performance and efficiency of RedCap devices in various application scenarios. The proposed technique seeks to enhance data rates, reduce latency, and extend battery life while maintaining the cost-effectiveness and simplicity essential for RedCap devices. Consequently, the proposed design effectively overcomes prior challenges and boosts system throughput by leveraging the power domain to transmit supplementary data bits, all while preserving a streamlined and uncomplicated transceiver design. In summary, with the same time, frequency, space, and power resources, it can be served an additional user with a stream of data bits equal to that of the main user, thus resulting in doubling the system’s spectral efficiency
An Experimental Study on Determination of Optimal Tilt and Orientation Angles in Photovoltaic Systems
No full textThis paper determines the most suitable azimuth and tilt angles for photovoltaic (PV) panels to generate electricity from solar energy. Literature reviews typically focus on maximizing radiation values on fixed panels. However, this study identifies the optimal position for maximizing the total radiation falling on PV panels with varying azimuth and tilt angles. An experimental setup is established to measure solar radiation, power, and temperature data. The electrical energy, open-circuit voltage, and short-circuit current produced by the PV panels are measured and recorded simultaneously. The performance of PV panels at different azimuths and tilts on power output is examined and compared. Experimental results have indicated that panel tilt and azimuth angles significantly impact power generation, currents, and fill factor. Based on the theoretical and experimental results obtained, the optimal tilt angle on the horizontal plane for Konya province, T ; uuml;rkiye, is determined to be 32.08 degrees, with the most suitable azimuth angle being 0 degrees. This article could serve as a suitable guide for finding the optimal tilt angle for similar locations in the future.The authors would like to express their gratitude to the General Directorate of Meteorology for its contributions to the data. This work was supported by the Coordinatorship of Selcuk University's Scientific Research Projects under Grant 20211002.Coordinatorship of Selcuk University's Scientific Research Projects [20211002