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Experimental and Numerical Study on Seismic Performance of Strap Braced Cold Formed Steel Shear Walls
No full textLight steel structures have significantly increased in recent years. These buildings stand out due to their relatively lower weight compared to other structural elements, ease and speed of assembly, and design flexibility. Strap-braced panel elements are designed to resist the lateral loads of the system. In this study, experiments and numerical analyses of strap-braced panel elements in light steel structures were conducted. Within this scope, five different panel elements with various configurations were examined. Specimens with and without strap braces, those with braces on both sides, and samples with different aspect ratios were tested. Reversible cyclic loading was applied, and the results were presented through load-displacement curves. Based on these curves, the strength and stiffness values of the elements were calculated. Additionally, the failure modes of the specimens were analyzed, and the experimental results were compared with numerical analysis outcomes. Furthermore, an evaluation was made based on the behavior factor calculated from the experimental results. According to the findings, the panel with a 1:1 aspect ratio and strap braces on both sides exhibited superior strength compared to other elements. Based on these results, a simple and effective strengthening proposal is presented for light steel structures, which are initially constructed as temporary buildings but later become permanent in disaster situations.Hafif çelik yapılar son yıllarda önemli ölçüde artmaktadır. Bu binalar diğer yapı elemanlarına göre nispeten daha hafif olması, kolay ve hızlı montajları ve tasarım esnekliği sunması gibi özellikleri ile öne çıkmaktadır. Şerit çaprazlı panel elemanlar ise sistemin yatay yüklerini karşılamak üzere tasarlanmaktadır. Bu çalışmada hafif çelik yapılarda şerit çaprazlı panel elemanların deneyleri ve bunlara ait nümerik analizleri yapılmıştır. Bu kapsamda farklı konfigürasyonlara sahip beş farklı panel eleman irdelenmiştir. Panel elemanda şerit çaprazın olup olmadığı, her iki yüzde çaprazın olup olmadığı gibi durumlarla birlikte farklı en-boy oranına sahip numuneler test edilmiştir. Bunun için tersinir çevrimsel yükleme esas alınmış olup, elde edilen sonuçlar yük-deplasman eğrileri ile gösterilmiştir. Bu eğrilere göre elemanlara ait dayanım ve rijitlik değerleri hesaplanmıştır. Bunlarla birlikte çalışmada numunelerin göçme modlarına yer verilmiş olup deneysel sonuçlar nümerik analiz sonuçları ile mukayese edilmiştir. Ayrıca deneysel sonuçlara göre hesaplanan davranış katsayısı üzerinden bir değerlendirmeye yer verilmiştir. Deneysel sonuçlara göre 1:1 en-boy oranına sahip her iki yüzünde de şerit çapraz bulunan panelin diğer elemanlara göre dayanım yönünden daha iyi olduğu görülmüştür. Elde edilen sonuçlara istinaden afet durumlarında geçici olarak yapılan ancak kalıcı binalara dönüşen hafif çelik yapılar için basit ve etkili bir güçlendirme önerisine yer verilmiştir
Recovering Levulinic Acid by Adsorption Using Efficient Basic Anion Exchangers
No full textLevulinic acid (LA) is a versatile compound used in biofuels, resins, etc., and its efficient recovery is required for its high value-added use. This study investigates the use of four anion exchange resins -Lewatit M-500 (a strong basic anion exchanger) and three weak basic anion exchangers (WBAEs), namely Amberlite IRA-67, Lewatit MP-62, and Lewatit MP-64- for LA recovery. The effects of pH, agitation time, LA concentration, resin dosage, and temperature on the adsorption efficiency were studied via batch experiments. Solution pH significantly influenced the yield. The highest efficiency was obtained at pH 2.1 for the WBAEs and pH 5 for Lewatit M-500. The kinetic data followed the pseudo-second-order model with R-2 >0.99. Increasing temperature slightly decreased the efficiency, with negative values for enthalpy (Delta H degrees) and Gibbs free energy (Delta G degrees), suggesting that the process was spontaneous and exothermic. The yield increased with resin dosage but decreased with higher initial LA concentrations. The highest adsorption capacity obtained from the four resins followed the order: Lewatit MP-62 (487.7 mg/g) > Amberlite IRA-67 (418.0 mg/g) > Lewatit MP-64 (371.6 mg/g) > Lewatit M-500 (278.7 mg/g). The successive adsorption-desorption trials using Lewatit MP-62 showed a slight decline (90% to 85%) in recovery efficiency over five cycles.The authors wish to acknowledge Konya Technical UniversityKonya Technical University Scientific Research Projects (BAP) Coordination Unit; Konya Technical Universit
Kalın Cidarlı Düşey Borularda Doğal Taşınım ile Birleşik Isı Transferinin İncelenmesi
No full textConjugate natural convection heat transfer at steady state with internal laminar flow in thick-walled vertical pipes is investigated by considering the wall and axial fluid conduction. The problem is addressed in a vertical and axisymmetric pipe of finite length with a constant external surface temperature boundary condition. Neglecting the viscous dissipation and assuming that all fluid properties are constant except the density in the buoyancy term by the Boussinesq approximation, the problem is solved numerically by the finite difference method and the set of coupled equations; continuity, momentum and energy, are solved simultaneously. For the velocity solution SIMPLE algorithm with a staggered grid system is used and axial and radial velocity and pressure distributions in the pipe are obtained. The energy equations are also simultaneously solved for both the wall and the fluid sides by considering continuity conditions at the interface and the bulk temperature, interfacial heat flux and local Nusselt number distributions are determined. The effects of the dimensionless parameters defining the problem, which are Grashof number, GrL, Prandtl number, Pr, ratio of wall to fluid thermal conductivity, kwf, wall thickness ratio, d' and pipe length to radius ratio, B, on the flow and heat transfer characteristics, are investigated. Solutions were made for different values of these parameters. GrL=105, 106, 107 and 108; Pr=0.7, 4.7, 50 and 100; kwf =1, 10, 100 and 1000; d'=0.02, 0.1 and 0.3; B=16, 24, 32, 40 and 48. The interfacial heat flux reaches high values in regions very close to the entrance, then decreases rapidly and drops to zero in the thermally developed region. As the Grashof and Prandtl numbers increase, the interfacial heat flux values and total heat transfer also increase. Again, for large Grashof and Prandtl numbers, the hydrodynamic and thermal development distances are longer. It is observed that the thermal development distances decrease as the pipe length to radius ratio increases. Again as the pipe length to radius ratio increases, the flow rate and accordingly the interfacial heat flux values decrease.Kalın cidarlı düşey borularda, sürekli rejimde boru içi laminer akış doğal taşınım ile birleşik ısı transferi cidar ve eksenel akışkan iletimi dikkate alınarak incelenmiştir. Problem düşey ve sonlu uzunluktaki eksenel simetrik bir boruda sabit dış yüzey sıcaklığı sınır şartı ile ele alınmıştır. Viskoz sönüm ihmal edilerek, Boussinesq yaklaşımı ile kaldırma kuvveti terimindeki yoğunluk hariç tüm akışkan özelliklerinin sabit olduğu varsayımıyla, problem sonlu farklar yöntemi ile sayısal olarak ve birbirine bağlı denklem takımı, süreklilik, momentum ve enerji denklemleri, eş zamanlı olarak çözülmüştür. Hız çözümü için kaydırılmış düğüm noktası sistemi ile SIMPLE algoritması kullanılarak boruda eksenel ve radyal hız ve basınç dağılımları elde edilmiştir. Enerji denklemi hem cidar ve hem de akışkan tarafı için arayüzeyde süreklilik şartları göz önüne alınarak çözülmüş ve yığık sıcaklık, ara yüzey ısı akısı ve yerel Nusselt sayısı dağılımları belirlenmiştir. Problemi tanımlayan boyutsuz parametrelerin ki bunlar; Grashof sayısı, GrL, Prandtl sayısı, Pr, cidar-akışkan ısı iletkenlik katsayısı oranı, kwf, cidar kalınlık oranı, d' ve boru uzunluğunun boru yarıçapına oranıdır, B, akış ve ısı transferi karakteristikleri üzerine etkileri incelenmiştir. Çözümler bu parametrelerin farklı değerleri için yapılmıştır. GrL=105, 106, 107 ve 108; Pr=0.7, 4, 7, 50 ve 100; kwf =1, 10, 100 ve 1000; d'=0.02, 0.1 ve 0.3; B=16, 24, 32, 40 ve 48. Arayüzey ısı akısı girişe çok yakın bölgelerde yüksek değerlere ulaşmakta, sonrasında hızla azalarak ısıl olarak gelişmiş bölgede sıfıra düşmektedir. Grashof ve Prandtl sayıları büyüdükçe arayüzey ısı akısı değerleri ve toplam ısı transferi de daha büyük olmaktadır. Yine büyük Grashof ve Prandtl sayıları için hidrodinamik ve ısıl gelişme mesafeleri daha uzun olmaktadır. Uzunluk-yarıçap oranı arttıkça ısıl gelişme mesafesinin kısaldığı görülmektedir. Yine uzunluk-yarıçap oranı arttıkça akış hızı ve buna bağlı olarak arayüzey ısı akısı değerleri de azalmaktadır
Cmacgsa: Improved Gravitational Search Algorithm Based on Cerebellar Model Articulation Controller for Optimization
No full textDandil, Emre/0000-0001-6559-1399; Yuzgec, Ugur/0000-0002-5364-6265Metaheuristic algorithms have gained significant attention in recent years for addressing complex and challenging optimization problems, especially in engineering. These algorithms often take inspiration from natural phenomena, systems or biological behaviour to find optimal solutions. Recent advances in the field often involve hybrid methods that combine several algorithms to improve performance. This study introduces an improved Gravitational Search Algorithm, named CMACGSA, which incorporates the Cerebellar Model Articulation Controller (CMAC)-a neural network model-to enhance the performance of Gravitational Search Algorithm (GSA). By employing the CMAC neural network, CMACGSA dynamically learns the masses of particles/agents of GSA, enabling a learning-driven approach to mass computation. Additional enhancements include L ; eacute;vy mutation, boundary control methods and an error handling mechanism, which together improve the robustness and adaptability of the algorithm. The effectiveness of CMACGSA is demonstrated through extensive testing on a set of 2D CEC 2014 benchmark functions, where it significantly outperforms the original GSA. Further evaluations on multidimensional CEC 2014 test problems, including 30-dimensional cases, reveal improved performance over widely used optimization algorithms and state-of-the-art (SOTA) algorithms. Furthermore, CMACGSA consistently achieves top-tier average performance metrics when benchmarked against four well-established GSA variants. The applicability of the algorithm is further validated by engineering design problems where it demonstrates outstanding performance, confirming its value in solving complex engineering challenges
Investigation of Gamma-Ray Radiation Shielding Properties of Zinc Borate and Paraffin Filled Sheep Wool Biopolymer Composites: Experimental and Theoretical Analysis
No full textThe present study examines the potential of sheep wool biopolymer composites filled with zinc borate and paraffin wax additives as a gamma-ray radiation shielding material. The selected novel composite samples were prepared with varying proportions of additive materials (10, 20, 30, and 40 wt%) so that impact of the additive amount on radiation shielding could be properly analyzed. Evaluations of specimens were performed at different energy levels ranging from 20 keV to 1.3325 MeV with help of a NaI scintillation detector, MC simulation (GEANT4) and WinXCOM theoretical calculation code. Following the production of shielding samples, the characterization and structural evaluation was performed using X-Ray Diffraction (XRD) and field emission scanning electron microscope (FE- SEM /EDX) supported by EDAX energy dispersive X-ray spectroscopy. The results demonstrate that the incorporation of additives into composite materials enhances the gamma attenuation capacity. The optimal gamma shielding performance is achieved with a 40 wt% ZnB40 composition, which exhibits superior shielding efficacy at lower gamma-ray energies. The MAC value of ZnB40 at 20 keV is about 2.7343 times higher than one of ZnB10 while it is about 1.2675 times greater at 80.9 keV. Moreover, it can be safely said that ZnB40 material can be a suitable option for insulating dentist rooms or buildings that require the use of regular aprons.Konya Technical University [232222028]The authors acknowledge that this project was supported by the Scientific Research Coordinator of Konya Technical University with project number 232222028
Large-Area Deposition of Hydrophobic Poly(Hexafluorobutyl Acrylate) Thin Films on Wetting-Sensitive and Flexible Substrates Via Plasma-Enhanced Chemical Vapor Deposition
No full textIn this study, hydrophobic poly(hexafluorobutyl acrylate) (PHFBA) thin films were successfully deposited over a large area of 25 x 50 cm using plasma-enhanced chemical vapor deposition (PECVD). Key parameters, including plasma power and the distance between the plasma antenna and the substrate, were optimized to achieve the highest deposition rate while ensuring uniformity and defect-free coatings. The optimal conditions were determined as 5 W plasma power and a 9 cm antenna-substrate distance, yielding a maximum deposition rate of 11.3 nm/min. PHFBA's low fluorine content makes it a more environmentally and biologically friendly alternative compared to heavily fluorinated polymers, addressing concerns about toxicity and environmental impact. The coatings were applied to a flexible and wetting-sensitive paper towel substrate, which was successfully coated without any visible defects. The contact angle measurements confirmed the hydrophobic nature of the films, with a maximum water contact angle of 131.9 degrees after the deposition of PHFBA. This study highlights the potential of PECVD as an efficient and scalable method for producing hydrophobic coatings, combining high-performance properties with improved environmental considerations. The results not only validate PECVD as a scalable and precise method for thin film fabrication but also open new possibilities for its use in applications requiring durable and functional surface modifications.This study was supported by the Scientific and Technological Research Council of Turkey (TUB ; Idot;TAK) with a grant number of 119M227.Scientific and Technological Research Council of Turkey (TUBIdot;TAK) [119M227
İmar Barışının Teknik ve Sosyal Etkilerinin Değerlendirilmesi
No full textWith the Zoning Peace Regulation, which was put into practice with the temporary article 16 included in the Law No. 7143 on the Restructuring of Taxes and Certain Other Receivables and Amending Certain Laws and added to the Zoning Law No. 3194, a regulation has been made regarding the occupation of illegal buildings and treasury lands in our country. ; Building Registration Certificates were issued according to the declarations of citizens via the E-Government System. In this study, following the Zoning Peace Law enacted in our country in 2018, the problems faced by the citizens after receiving the Building Registration Certificate, the problems they experienced with their environment, the impact of the Zoning Peace on illegal construction, and the citizens who did not apply for the Zoning Peace and those who applied were researched and the zoning peace received in Konya province. Evaluations were made by examining the data regarding the status of the applications and the results of the audit activities. The extension of the application and payment process for zoning amnesty causes destruction in areas that need to be protected, at the same time, citizens can make updates with price increasing transactions via E-Government, these applications increase the expectation of a new application, encourages people to engage in illegal construction, and some legal regulations need to be made for this purpose. It was determined that it was needed. It has been observed that citizens act unconsciously about illegal construction and consider illegal construction as normal.7143 Sayılı, Vergi ve Diğer Bazı Alacakların Yeniden Yapılandırılması ile Bazı Kanunlarda Değişiklik Yapılmasına İlişkin Kanunda yer alan ve 3194 Sayılı İmar Kanunu'na da eklenen geçici 16. madde ile uygulamaya konulan İmar Barışı Düzenlemesi ile Ülkemizdeki kaçak yapı ve hazine arazilerinin işgaline ilişkin düzenleme yapılmış olup; E-Devlet Sistemi üzerinden vatandaşların beyanlarına göre Yapı Kayıt Belgeleri düzenlenmiştir. Bu çalışma ile ülkemizde 2018 yılında çıkarılan İmar Barışı yasası sonrasında vatandaşların Yapı Kayıt belgesi aldıktan sonra karşılaştıkları sorunları, çevreleri ile yaşadıkları problemleri, İmar Barışının kaçak yapılaşma konusunda yarattığı etkiyi gerek imar barışı başvuru yapmayan ve başvuru yapan vatandaşlar üzerinde araştırma yapılmış ve Konya ilinde alınan imar barışı başvuruların durumları ve denetim faaliyetleri sonuçlarına ilişkin veriler incelenerek değerlendirmeler yapılmıştır. İmar affına başvuru ve ödeme sürecinin uzatılmasının korunması gereken alanlarda tahribata sebep verdiği, aynı zamanda vatandaşın E-Devlet üzerinden bedel arttırıcı işlemler ile güncelleme yapabildiği, bu uygulamaların yeni bir uygulama çıkacağı beklentisini arttırdığı, insanları kaçak yapılaşmaya teşvik ettiği ve buna yönelik yapılması gereken bazı yasal düzenlemelere ihtiyaç duyulduğu tespit edilmiştir. Vatandaşların kaçak yapılaşma konusunda bilinciz davrandığı ve kaçak yapılaşmayı normal karşıladığı görülmüştür
Effect of Hetero-Atom Doping on the Structure and Optical Properties of Carbon Quantum Dots for the Sensitive Detection of Heavy Metal Ions
No full textMetal pollution in water sources due to modernization is a human health and environmental problem. Therefore, the highly fluorescent boron- and nitrogen-doped and nitrogen-doped carbon quantum dots (B,N-CQDs and N-CQDs, respectively) were synthesized and investigated to be used as a fluorescence sensor for metal ion detection. In this study, the synthesized B,N-CQDs and N-CQDs had an average size of 4-6 nm and 3-4 nm, respectively. The B,N-CQDs presented high sensitivity as 0.0090, 0.0086 and 0.0091 units per micromolar for Cr3+, Cu2+ and Fe2+, respectively, whereas the N-CQDs showed sensitivity as 0.0047, 0.0102, 0.0095 and 0.0121 units per micromolar for Cr3+, Cu2+, Fe2+ and Ni2+, respectively. In the concentration range of 10-80 mu M, the detection limits of B,N-CQDs and N-CQDs were found to be in the range of 13.9-65.5 mu g/L and 14.9-38.3 mu g/L, respectively. The result of the study clearly indicates that B,N-CQDs and N-CQDs can be seen as metal ion sensing devices with high sensitivity and low cost
Baffle Angle Optimization of a Typical Shell and Tube Heat Exchanger
No full textAn optimization study was conducted with the objective of enhancing the performance of a prevalent shell-and-tube heat exchanger model by modifying the baffle angles. The initial step was to verify the turbulence model results with numerical studies and analytical approaches documented in the literature. Subsequently, an investigation was conducted to address the contributions identified in the literature by determining the optimal angle for a shell-and-tube heat exchanger with six baffles. In the extant literature, the 36% baffle cut case, which is typically observed to provide the optimal heat transfer result, was selected for further analysis. A genetic algorithm optimization model embedded in a program was employed to evaluate the heat transfer and pressure drop jointly, thereby determining the optimal angles for all baffles. According to the performance evaluation criteria that considered both heat and flow results, the optimal angles were found to be 315 degrees, 195 degrees, 80 degrees, 340 degrees, 250 degrees, and 95 degrees from the first to the last baffle, respectively. Additionally, a comparison was conducted between the cross-arrangement baffle and the optimized baffle, which demonstrated superior performance by 5.5% and 19.5%, respectively, contingent on the increasing flow rate. Moreover, the novel configuration enabled enhanced mixing of the flow, which exhibited periodic movement in the staggered baffle configuration within the shell. This resulted in a notable enhancement of the heat transfer process
Evrişimli Sinir Ağları ile Mevcut Betonarme Binaların Yükseklik, Yumuşak Kat ve Kısa Kolon Tespitlerinin Yapılması
No full textGiven Turkey's location on an active and significantly important earthquake belt, it is crucial to conduct risk analyses of our existing building stock and prioritize risks to implement effective and improvable measures. In Turkey, there is a need to assess hundreds of thousands of buildings, particularly residential ones, in cities for earthquake risk analysis. Despite the existence of many rapid seismic evaluation methods, determining the earthquake risk priority order of buildings entails significant cost and time due to the large number of residential buildings in the building inventory. Additionally, the need for analysis of a large number of buildings will require the assignment of numerous technical experts, leading to differences in interpretation based on their knowledge, expertise, and experience in the relevant field. Furthermore, evaluating buildings based on numerous parameters due to their earthquake risk may deviate from the standard and result in different expert opinions, leading to challenges in the evaluation process. Standardization of evaluation as much as possible is crucial for making decisions more rapidly and measurably in critical decisions such as earthquake risk analysis. Therefore, leveraging smart systems in a solution-oriented, functional, economical, and standardized manner is crucial for conducting earthquake risk analyses of existing buildings in Turkey, which is an extremely vital and serious issue. Especially in recent years, smart systems have been frequently used in solving complex engineering problems dependent on multiple parameters. Thus, this thesis aims to analyze the results obtained by analyzing the objects with the YOLO (You Only Look Once) CNN convolutional neural network object detection algorithm, which can predict floor height, soft story, and short column formation parameters from building facade images, assisting expert engineers in pre-earthquake risk analysis of residential reinforced concrete buildings and facilitating decision-making in the absence of technical experts. As a result, the labeling of objects and the detection of objects via visuals (62% except for the clestory) as a result of the 1st, 2nd and finally 3rd process was determined with an accuracy rate of 99.3%. In addition, the average height values of the detected objects were calculated and the building height was obtained. Keywords: Earthquake, Rapid Seismic Assessment, Soft Story, Short Column, YoloÜlkemiz aktif deprem kuşağı üzerinde yer alması sonucunda mevcut bina stokumuzun risk analizlerinin yapılarak risk önceliklerinin belirlenmesi etkin ve geliştirilebilir önlemlerin alınması hayati önem arz etmektedir. Türkiye'de deprem öncesi mevcut binaların risk analizi için şehirlerde bulunan özellikle konut türü yüz binlerce binanın incelenmesine ihtiyaç duyulmaktadır. Mevcutta kullanılan ve sürekli geliştirilen birçok hızlı sismik değerlendirme yöntemi olmasına rağmen binaların deprem risk öncelik sırasının belirlenmesi, yapı envanteri içerisinde yer alan konut türü bina sayısının çok fazla olması nedeniyle oldukça büyük bir maliyet ve uzun bir süreç gerektirmektedir. Bunun yanı sıra araştırılıp analizi yapılması gereken bina sayısının fazla olması ile çok sayıda teknik uzman görevlendirilmesine de sebep olacaktır. İlgili alanlardaki teknik uzmanların değerlendirmesinde uzmanın bilgi, birikim ve çalıştığı iş kolundaki tecrübesine göre yorum farklılıkları olmasına sebep olacaktır. Ayrıca incelenecek binaların deprem riski göz önünde bulundurulduğundan çok fazla parametreye göre değerlendirilmesi standarttan uzaklaşmaya ve farklı uzman görüşlerin olması değerlendirmede sorunların oluşmasına yol açacaktır. Deprem risk analizi gibi hayati bir konuda verilen kararlarda değerlendirmenin mümkün olduğunca standart yapılması, kararların daha hızlı ve ölçülebilir şekilde alınması oldukça büyük önem arz etmektedir. Bu durumda Türkiye için son derece hayati ve ciddi bir konusu olan mevcut binaların deprem risk analizlerinin çözüm odaklı, fonksiyonel, ekonomik ve standartlaşma ile sağlıklı bir şekilde gerçekleştirilmesinde akıllı sistemlerden faydalanmak mümkün olduğunca doğru sonuçlara varmak adına önem taşımaktadır. Özellikle son yıllarda sayıca fazla olan ve çoklu parametrelere bağlı karmaşık mühendislik problemlerin çözümünde akıllı sistemler sıklıkla kullanılmaya başlanmıştır. Buradan hareketle bu tezde; konut türü betonarme binaların deprem öncesi risk analizinde uzman mühendise yardımcı olacak (ya da teknik uzman yokluğunda karar vermeyi kolaylaştıracak) ve risk önceliklendirilmesinde kullanılacak parametrelerden olan kat yüksekliği, yumuşak kat ve kısa kolon oluşumu durumlarını bina cephe görselleri üzerinden tahmin edebilen YOLO (You Only Look Once) CNN evrişimli sinir ağları nesne algılama algoritması ile analiz edilerek bulunan sonuçların değerlendirilmesi yapılmıştır. Sonuç olarak nesnelerin etiketlenmesi ve uygulanan 1., 2. ve son olarak uygulanan 3. işlem neticesinde görsel üzerinden nesnelerin tespiti (asma kat hariç %62) %99,3 doğruluk oranı ile tespit edilmiştir. Ayrıca tespit edilen nesnelerin ortalama yükseklik değerleri hesaplanarak bina yüksekliği elde edilmiştir. Anahtar kelimeler: Deprem, Hızlı Sismik Değerlendirme, Yumuşak Kat, Kısa Kolon, Yol