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The main purpose of this investigation was to explore the heat transfer and flow characteristics of aero-foil-shaped fins combined with extended jet holes, specifically focusing on their feasibility in cooling turbine blades. In this study, a comprehensive investigation was carried out by applying impinging jet array cooling (IJAC) on a semi-circular curved surface, which was roughened using aerofoil-shaped fins. Numerical computations were conducted under three different Reynolds numbers (Re) ranging from 5000 to 25,000, while nozzle-to-target surface spacings (S/d) ranged from 0.5 to 8.0. Furthermore, an assessment was made of the impact of different fin arrangements, single-row (L1), double-row (L2), and triple-row (L3), on convective heat transfer. Detailed examinations were performed on area-averaged and local Nusselt (Nu) numbers, flow properties, and the thermal performance criterion (TPC) on finned and smooth target surfaces. The study’s results revealed that the use of aerofoil-shaped fins and the reduction in S/d, along with surface roughening, led to significant increases in the local and area-averaged Nu numbers compared to the conventional IJAC scheme. The most notable heat transfer enhancement was observed at S/d = 0.5 utilizing extended jets and the surface design incorporating aerofoil-shaped fins. Under these specific conditions, the maximum heat transfer enhancement reached 52.81%. Moreover, the investigation also demonstrated that the highest TPC on the finned surface was achieved when S/d = 2.0 for L2 at Re = 25,000, resulting in a TPC value of 1.12. Furthermore, reducing S/d and mounting aerofoil-shaped fins on the surface yielded a more uniform heat transfer distribution on the relevant surface than IJAC with a smooth surface, ensuring a relatively more uniform heat transfer distribution to minimize the risk of localized overheating.

Environmental problems have increased the need for sustainable agricultural practices that conserve water and energy. Carob, an eco-friendly crop with multiple health benefits, holds the potential for economic evaluation. This study investigates the carob molasses extraction process, focusing on the influence of temperature and water quantity on the diffusion coefficient. The rheological behavior of carob molasses was analyzed experimentally, and a model was developed to optimize energy consumption during the extraction process. The impact of temperature on the mass transfer coefficient was examined using the Arrhenius approach, with the extraction conducted at a maximum of 50 °C to prevent caramelization. The activation energy for carob extraction was determined to be 5.475 kJ/mol, and a new equation is proposed for estimating the mass transfer coefficient.

Numerical studies were performed in this study to analyze the effect of dimensionless elongated injection holes ( G/d  = 0.5, 2.0, 4.0, 8.0) on heat and flow characteristics on rib-roughened surfaces with an array of inclined impingement jets. Experimental and numerical data from existing literature were used to validate the numerical solution procedure’s heat transfer and flow characteristics in the semicircular test section. The turbulence equations were solved using the SST k-ω turbulence model by varying the Reynolds number from 5000 to 25,000. The curvature effect and staggered array pattern created an additional stagnation region between adjacent impinging jets on smooth surfaces, leading to a low heat transfer zone. Rectangular cross-sectional V-shaped ribs ( VSR ) were placed in regions where the stagnation point occurs to eliminate this disadvantage. The effect of different normalized rib heights ( H r /d  = 0, 0.2, 0.3, 0.4) and rib angles ( α  = 30°, 45°, 60°, 90°) on the curved surface was also investigated to increase convective heat transfer performance and achieve more homogenous heat transfer distribution by relatively reducing the effect of thermal stresses. Flow properties, area-averaged and local Nusselt number variations on smooth and ribbed surfaces, and the thermal performance criterion ( TPC ) were investigated in detail. The results indicated an increase in overall heat transfer and a more evenly distributed measurement region compared to the conventional (unextended jet and smooth surface) jet impingement configuration. The most significant heat transfer enhancement from combining the elongated jets with VSR was 47.23% at H r /d  = 0.2 by reducing the G/d to 0.5. In addition, the highest TPC was determined as 1.07 on the proposed model with G/d  = 2.0 and H r /d  = 0.2 at Re = 25,000.

Nanofluids have high thermal conductivity and can be used as vehicle engine coolant. In this article, the effects of Al2O3 nanoparticles to an engine coolant were experimentally investigated and the results were compared with the results of the original coolant including 50% ethylene glycol and 50% water mixture. The nanofluid was prepared by adding 0.5% Al2O3 nanoparticles by volume. The inlet temperature of the coolant was held constant at 95?C. The tests were carried out at the air inlet temperatures between 23.4-28.6?C, the air velocity be-tween 1.7-4.3 m/s, the cooling power between 2.5-15 kW and the cooling fluid flow rates between 10-25 Lpm. The results show that nanoparticles increase the cooling performance of the engine radiator. By using Al2O3 nanoparticles, cooling power of the radiator has increased up to 17.46% compared to original case.

In this study, the heat transfer mechanism under agitated pool boiling was examined experimentally. Aqueous sugar solutions were used in a centrically agitated vessel. The effects of the gap which is between the impeller edge and the flat bottom of the agitated vessel, the rotational impeller speed and impeller size were studied on the boiling heat transfer coefficient. A new Nusselt function depending on the Peclet number was suggested for the heat transfer mechanism. nema

In this study, performance of a heat exchanger used in combi boilers was investigated numerically for different fin geometries. Analyses were performed at the boiler operation conditions. A commercial CFD software package, FLUENT, was used for numerical simulations. The 3-D steady-state turbulent flow field analysis was carried out and k-? model was preferred as the turbulence model. In the analysis, it was assumed that the heat transfer phenomenon occurred both by conduction and convection. Flat fin geometry was taken as a reference for the investigation. Variation of the heat transfer and pressure drop values for the wavy fin were compared with the reference geometry. The wave angle and wave radius were taken as the parameters for the wavy fins. For different fin geometries: the outlet temperaTure of the combustion gases, the heat transfer to the water, and the pressure drop were calculated and the results were presented. Compared with flat fin, average decrease for the outlet temperature of hot gases was obtained as 4 K and average increase for the heat transfer to the water was calculated as 0.68 W. On the other hand, the average pressure drop in the heat exchanger with wavy fins was about 70% higher than the flat fin. nema

Günümüzde şekerleme endüstrisinde, akide şekeri, helva ve birçok yöresel ve modern şekerleme üretiminde şekerden üretilen gıdalara şekil verilebilmesi ve katkı maddeleri (renk, aroma vs.) ilave edilebilmesi için şekere su ilave edilerek şeker su çözeltileri oluşturulmaktadır. Bu çözeltiler karıştırıcılı tanklarda kaynatılarak su uzaklaştırılır ve helva türündeki bu tatlıların üretiminde esas bileşen olarak kullanılan yoğun kıvamlı sulu şeker çözeltileri başka bir deyişle şeker ağdası elde edilir. Helva ve helva türündeki bu tatlılar, Yunanistan, Türkiye ve Arap ülkeleri gibi birçok orta doğu ülkesinde oldukça yaygın olarak tüketilmektedirler.Karıştırma sayesinde ısı geçişinin iyileştiği iyi bilinmektedir. Bu yüzden ısı geçişini iyileştirmek için endüstriyel üretimde karıştırıcılı kaplara oldukça fazla rastlanılmaktadır. Buna rağmen bu özel konu ile ilgili çok az araştırma bulunmaktadır. Mevcut araştırmalar ise genellikle saf maddelerin ısıtılması veya soğutulması sırasında karıştırmanın ısı geçişine olan etkisi incelenmektedir. Yapılan literatür araştırması, öngörülen çalışmanın henüz yapılmadığını göstermektedir.Bu çalışmada, kaynatma yapılan karıştırıcılı tanklarda havuz kaynaması esnasındaki ısı geçiş mekanizması deneysel olarak incelenmiştir. Deneylerde gıda endüstrisinde oldukça yaygın olarak kullanıldığından ve sabit basınçta farklı sıcaklıklarda doymuş haller elde etmek mümkün olduğundan sulu şeker çözeltileri kullanılmıştır. Taban yüzeyinden ısıtılan karıştırıcılı tanklarda, farklı derişikliklere sahip sulu şeker çözeltileri için karıştırıcı kanadın dönme hızı, kanat boyutu ve kanat ile taban arasındaki mesafe gibi parametrelerin ısı geçişine olan etkileri araştırılmıştır. Isı geçişinin derişiklik ve devir sayısına büyük oranda bağlı olduğu görülmüştür. Reynolds sayısının maksimum 1100 olduğu laminer akış durumunda ısı akısını hesaplayabilmek için Peclet sayısına bağlı iki farklı tipte Nusselt fonksiyonu önerilmiştir. Deneysel verilerden elde edilen Nusselt sayıları ile önerilen fonksiyonlardan hesaplanan Nusselt sayılarının birbirlerine yakın çıktığı görülmüştür.

Doğrusal olmayan robot kolları çok karmaşık dinamik karakteristiklere sahiptirler. Dış bozucu büyüklükler, sürtünme ve eyleyicilerin doyuma ulaşması gibi nedenlerden ötürü geleneksel tip kontrolörlerle dayanıklı kontrol zordur. Sadece zor olmakla kalmaz aynı zamanda geleneksel kontrolörler robot manipülatörünün detaylı dinamik modeline ihtiyaç duyarlar. Bu çalışmada yapay sinir ağları, bulanık mantık ve model referans adaptif kontrol dinamik sinirsel bulanık mantık kontrolörü yapısı altında birleştirildi. Önerilen kontrolör bulanık kural yapısını ve üyelik fonksiyonlarının parametrelerini ayarlayabilmek için öğrenme yeteneğine sahiptir. Çalışmanın sonunda bir, iki ve üç serbestlik dereceli robot kollarına verilen yörüngeler izlettirilmiş ve performans değerleri gözlemlenmiştir.

Objectives: To compare the effectiveness of expert-designed machine learning models and code-free automated machine learning (AutoML) models in classifying optical coherence tomography (OCT) images for detecting age-related macular degeneration (AMD) and distinguishing between its dry and wet forms. Materials and Methods: Custom models were developed by an artificial intelligence expert using the EfficientNet V2 architecture, while AutoML models were created by an ophthalmologist utilizing LobeAI with transfer learning via ResNet-50 V2. Both models were designed to differentiate normal OCT images from AMD and to also distinguish between dry and wet AMD. The models were trained and tested using an 80:20 split, with each diagnostic group containing 500 OCT images. Performance metrics, including sensitivity, specificity, accuracy, and F1 scores, were calculated and compared. Results: The expert-designed model achieved an overall accuracy of 99.67% for classifying all images, with F1 scores of 0.99 or higher across all binary class comparisons. In contrast, the AutoML model achieved an overall accuracy of 89.00%, with F1 scores ranging from 0.86 to 0.90 in binary comparisons. Notably lower recall was observed for dry AMD vs. normal (0.85) in the AutoML model, indicating challenges in correctly identifying dry AMD. Conclusion: While the AutoML models demonstrated acceptable performance in identifying and classifying AMD cases, the expert-designed models significantly outperformed them. The use of advanced neural network architectures and rigorous optimization in the expert-developed models underscores the continued necessity of expert involvement in the development of high-precision diagnostic tools for medical image classification. Keywords: Age-related macular degeneration, AutoML, convolutional neural networks, EfficientNet V2, optical coherence tomography

The adverse health and environmental effects of petroleum-based materials have become a driving force for the fabrication of bio-based monomers. In this study, we synthesized a novel bio-based reactive phosphorus-containing; eugenol-DOPO, which was prepared in one step by the reaction of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and eugenol via Atherton–Todd reaction. Moreover, a diallyl compound was also prepared by using eugenol and piperazine. All monomers were characterized by nuclear magnetic resonance (NMR), mass, and Fourier-transform infrared (FTIR) spectroscopies. Thiol-ene photocured polysulfide thermoset networks were prepared by using these newly synthesized bio-based monomers. Thermal and thermomechanical properties of the thermosets were measured. Photo-crosslinked networks displayed over 88% gel content values. The thermal stability of the networks as well as the resulting char yields were improved as the percentage of eugenol-DOPO was increased in the formulations. The presence of N and P played a synergistic effect and the limiting oxygen index (LOI) values for the thermoset materials were enhanced. We believe eugenol-DOPO is not only a good alternative monomer for the preparation of thermally stable photocurable thermosets, but it is also a suitable bio-based additive for other polymers as well.