Hızlı bir feribotun düşey ivmelenmesinin T-Foil ve trim tab sistem

his study is concerned with the active T-foil placed near the bow on the keel line of the fast ferry and two active trim tab controls placed at the stern to improve the maritime performance of a fast ferry, whilst improving the comfort and safety of passengers and crew. In the scope of the study, the vertical direction of the fast ferry under the random head waves, heave and pitch motions were taken into account. For the control of T-foil and trim Tabs, PID and LQR control methods were used. The purpose of these controllers is to reduce the acceleration of the heave and pitch motions of the fast ferry by changing the operating angles of the T-foil and trim tab wings. A random wave model was created using the Pierson-Moskowitz model, and simulations were done assuming that the fast ferry was subjected to random head waves. Finally, in order to see the effect of vertical acceleration on passengers, the rate of seasickness (MSI) change of the fast ferry in uncontrolled and controlled states was examined. Mathematical models of fast ferry, T-foil and trim tab and their simulations were carried out in MATLAB / Simulink environment. The simulation results show that T-foil and trim tab Active systems can effectively reduce vertical acceleration by improving heave and pitch motions.Bu çalışma, hızlı bir feribotun denizcilik performansını iyileştirmek, yolcu ile mürettebatın konfor ve güvenliğini artırmak için hızlı feribotun omurga hattında pruvaya yakın bir noktaya yerleştirilen hareketli T-foil ve kıç tarafına yerleştirilen iki adet hareketli trim tab kontrolü ile ilgilidir. Çalışma kapsamında baştan gelen düzensiz dalgaların etkisindeki hızlı feribotun düşey yönde yaptığı baş kıç vurma ve dalıp çıkma hareketleri dikkate alınmıştır. T-foil ve trim tabların kontrolü için ise PID ve LQR kontrol yöntemleri kullanılmıştır. Bu kontrolörlerin amacı, T-foil ve trim tab kanatlarının çalışma açılarının değiştirilmesiyle hızlı feribotun pozisyonunu kontrol ederek baş kıç vurma ve dalıp çıkma hareketlerinin ivmelenmesini azaltmaktır. Pierson-Moskowitz modelinden yararlanılarak düzensiz bir dalga modeli oluşturulmuş ve çalışmalar hızlı feribotun baştan gelen düzensiz dalgalara maruz kaldığı varsayılarak yapılmıştır. Son olarak düşey ivmelenmenin yolcular üzerindeki etkisini görebilmek için hızlı feribotun kontrolsüz ve kontrollü durumda deniz tutması oranı (MSI) değişimi incelenmiştir. Hızlı feribotun, T-foilin ve trim tabın matematiksel modelleri MATLAB / Simulink ortamında elde edilerek simülasyonları gerçekleştirilmiştir. Simülasyon sonuçları, T-foil ve trim tab aktif sistemlerinin baş kıç vurma ve dalıp çıkma hareketlerini iyileştirerek düşey ivmelenmeyi etkili bir şekilde azaltabildiğini göstermektedir

Sol anterior fasiküler bloğun stabil anginalı hastalarda sol ana ve/veya proksimal sol ön inen koroner arter hastalığının belirlenmesinde öngördürücü değerinin araştırılması: bir eğilim skoru eşleştirme analizi

Introduction: Successful revascularization of lesions located in the left main and/or proximal left anterior descending (LM and/or pLAD) coronary artery improves survival than medical therapy only. Therefore, accurate identification of high-risk patients with suspected stable angina pectoris is critical for outpatient clinics. Since the septal perforators of the left anterior descending coronary artery are the main source of blood supply of the left anterior fascicle, we hypothesized that the presence of left anterior fascicular block (LAFB) can predict obstructive stenoses of LM and/or pLAD coronary arteries in patients with suspected stable angina pectoris. Methods: We consecutively enrolled 790 patients referred for invasive coronary angiography due to suspected stable angina pectoris. Results: The number of patients with LAFB5 was 68 (8.6%). Furthermore, 218 patients (27.6%) had obstructive coronary artery disease (CAD). The prevalence of obstructive CAD, revascularization with coronary artery bypass graft surgery, and obstructive LM and/or pLAD coronary artery lesions was higher in patients with LAFB. From univariate analysis, the presence of LAFB was significantly associated with predicting obstructive LM and/or pLAD lesions (odds ratio: 3,587; 95% confidence interval: 1,465-5,785; p=0.005). However, this association disappeared after adjustment for other cardiovascular risk factors. Conclusion: In patients with suspected stable angina pectoris, LAFB is not frequently a 'normal variant" and is associated with known cardiovascular risk factors. It acts as a marker rather than a determinant of obstructive LM and/or pLAD coronary artery lesions

YAPAY SİNİR AĞLARI İLE ÜÇ BOYUTLU OBJE SINIFLANDIRMADA KONVOLÜSYON FİLTRELERİNİN ETKİSİNİN İNCELENMESİ

YAPAY SİNİR AĞLARI İLE ÜÇ BOYUTLU OBJE SINIFLANDIRMADA KONVOLÜSYON FİLTRELERİNİN ETKİSİNİN İNCELENMESİ ÖzetSonlu elemanlar analizi (FEA), yapıların fiziksel davranışlarını tespit etmek için bilgisayar ortamında tasarlanan ve belirli formülasyonlar ile çözülen simülasyon yöntemidir. Problemin büyüklüğüne veya karmaşıklığına göre hazırlık ve çözüm süresi artmaktadır. Sonlu elemanlar analizi için olması gerekenler, geometri ve sınır koşullarıdır. FEA’nın zor ve yorucu olmasının sebebi hazırlık aşamasının çok fazla girdi istemesidir. Ayrıca FEA yapabilmek için ileri düzeyde mühendislik bilgisi de gereklidir. Üç boyutlu yazıcı kullanımının artması da FEA’ya olan ihtiyacı arttırmıştır. Cep telefonu ve tabletlerin işlem gücünün gelişmesi ile sonlu elemanlar analizinin, girdiye ihtiyaç duymadan telefon kamerası ile yapılabilirliğinin mümkün kılınması adına altyapı oluşturulmuştur. Basit analizlerin otomatik olarak yapılabilmesi için derin öğrenme algoritmaları tasarlanmıştır ve eğitilmiştir. Hayatımızın her alanına giren yapay zekânın, sonlu elemanlar analizi alanında ne gibi çözümler sunacağı incelenmiştir. Ağ örgüsü (mesh) olmadan çözüm yapma hacimsel piksellenme metoduna dayandığı için bu çalışmada vokselizasyon tabanlı öğrenme üzerine inceleme yapılmıştır. Bu çalışmada, sonlu elemanlar analizi girdisi için gerekli olan üç boyutlu geometrik verilerin, bir kamera vasıtası ile taranan objelerin sınıflandırılmasına yarayacak yapay sinir ağı (YSA) oluşturulmuştur ve doruluğu test edilmiştir. Üç boyutlu geometrilerin sınıflandırılabilmesi için özelleştirilmiş bir evrişimli (konvolüsyonel) sinir ağı tasarlanmıştır. Çalışmada, üç boyutlu bilgisayar geometrilerinin konvolüsyon filtresine sahip yapay sinir ağları ile konvolüsyon fitresi bulundurmayan yapay sinir ağları arasındaki parametre sayısı, öğrenme süresi, öğrenme doğruluğu ve maliyet değerleri karşılaştırılmıştır. Konvolüsyon filtreli YSA’nın validasyon değeri %97,92’dir. Konvolüsyon filtresiz YSA %97,08 validasyon değeri ile öğrenme işlemini tamamlamıştır. Konvolüsyon filtresiz YSA eğitimi 440 saniyede tamamlarken, Konvolüsyon filtreli YSA’nın eğitimi 6260 saniye sürmüştür.Anahtar Kelimeler: Derin öğrenme, Yapay sinir ağı, Üç boyutlu obje sınıflandırma, Evrişimli sinir ağı, Konvolüsyon filtresi, Sonlu elemanlar analiziINVESTIGATION OF THE EFFECT OF CONVOLUTIONAL FILTERS ON THE THREE DIMENSIONAL OBJECT CLASSIFICATION BY ARTIFICIAL NEURAL NETWORKSAbstractFinite elements analysis (FEA) is a simulation method designed in a computer environment to determine the physical behavior of structures and solved with specific formulations. Depending on the size or complexity of the problem, preparation and solution time increases. The requirements for finite element analysis are geometry and boundary conditions. The FEA is difficult and tiring because the preparatory phase requires too much input. In addition, advanced engineering knowledge is required to perform FEA. The increase in the use of three-dimensional printers has increased the need for FEA. With the development of the processing power of mobile phones and tablets, an infrastructure was established to enable the feasibility of finite element analysis with telephone camera without the need for input. Deep learning algorithms are designed and trained in order to perform simple analysis automatically. What kind of solutions will be presented in the field of finite element analysis of artificial intelligence, which is included in every field of our lives, has been examined. Since the solution without mesh is based on the volumetric pixelation method, voxelization-based learning was investigated in this study. In this study, an artificial neural networks (ANN) was created and used for the classification of three-dimensional geometric data required for finite element analysis input and scanned objects by a camera. In order to classify three-dimensional geometries, a customized convolutional neural network was designed. In this study, the number of parameters, learning time, learning accuracy and cost values were compared between artificial neural networks with convolution filter of three dimensional computer geometries and artificial neural networks without convolution filter. The validation value of ANN with convolution filter is 97.92%. Without convolution filter ANN has completed the learning process with a validation value of 97.08%. While the ANN without convolution filter completed the training in 440 seconds, the ANN with convolution filter took 6260 seconds.Keywords: Deep learning, Artificial neural network, Three-dimensional object classification, Convolutional neural network, Convolution filter, Finite elements analysi

AA1050 ALÜMİNYUM`A SiO2 İLAVESİNİN MEKANİK DAVRANIŞLARA ETKİSİ

AA1050 ALÜMİNYUM`A SiO2 İLAVESİNİN MEKANİK DAVRANIŞLARA ETKİSİÖzetModern mühendislik alanlarında kaydedilen yeni gelişmeler, geleneksel metal ve alaşımlarının yeni hizmet alanlarının ihtiyaçlarını karşılayamadığı için, yeni malzemelere olan talepleri de arttırmaktadır. Metal matrisli kompozitlerin üretiminde en yoğun kullanılan metal alaşımları, düşük yoğunlukları ve kolay üretilebilirlikleri nedeniyle alüminyum alaşımlarıdır. Alüminyum ve alaşımlarının iyi özelliklerinin yanı sıra mekanik özelliklerinin düşük olması gibi bazı önemli dezavantajlarının olması bu malzemelerin kullanımlarını sınırlandırmaktadır. Ticari alüminyum ve alaşımlarının bu olumsuz özelliklerinin giderilmesinde kullanılan en yaygın yöntemlerden birisi de bu malzemelere sert takviye elemanları ilave etmektir. Bu şekilde bu malzemelerin dayanım ve sertlikleri önemli derecede artırılmaktadır. Bu çalışmada alüminyum matrisli nano SiO2 takviyeli kompozit malzeme üretimi yapılmıştır. Nano SiO2oranı olarak ağırlıkça%3 ve%1,5 oranlarında karıştırılarak AA1050 malzeme referansı üzerinden çekme testi ile meydana gelen mekanik davranışlardaki değişimler incelenmiştir. Kompozit malzemenin çekme mukavemet değerlerinde artış %3 nano SiO2 karışımında tavsız haddelenmiş değişik kalınlıklarda alınan numunelerin çekme analizi sonucunda ortalama %8,61 artış tespit edilmiştir. Malzemenin mukavemet değerlerinde artış %1,5 nano SiO2 karışımında tavsız haddelenmiş değişik kalınlıklarda alınan numunelerin çekme analizi sonucunda ortalama %4,42 artış tespit edilmiştir. Malzemenin çekme mukavemet değerlerinde artış %3 nano SiO2 karışımında tavsız haddelenmiş daha sonrasında tavlanıp H0 yapılmış değişik kalınlıklarda alınan numunelerin çekme analizi sonucunda ortalama %4,37 artış görülmüştür. Malzemenin mukavemet değerlerinde artış %1,5 nano SiO2 karışımında tavsız haddelenmiş daha sonrasında tavlanıp H0 yapılmış değişik kalınlıklarda alınan numunelerin çekme analizi sonucunda ortalama %3,99 artış sağlamıştır. Yapılan çalışmada optimum %1,5 SiO2 miktarının alüminyum malzemenin mukavemet değerlerini önemli ölçüde arttırdığı tespit edilmiştir.Anahtar Kelimeler: Alüminyum matrisli nano SiO2 takviyeli kompozit malzeme, Nano SiO2 nano kompozit malzeme, Alüminyum kompozitTHE EFFECT OF SiO2 ADDITION TO AA1050 ALUMINUM ON MECHANICAL BEHAVIORAbstractNew developments in the field of modern engineering increase the demand for new materials as traditional metals and alloys cannot meet the needs of new service areas. The most commonly used metal alloys in the production of metal matrix composites are aluminum alloys due to their low density and easy productionability. The good properties of aluminum and their alloys, as well as their low mechanical properties, have some important disadvantages that limit their use. One of the most common methods used to eliminate these negative properties of commercial aluminum and its alloys is to add rigid reinforcing elements to these materials. In this way, the strength and hardness of these materials are significantly increased. In this study, aluminum matrix nano SiO2 reinforced composite material was produced. Nano SiO2 ratio of 3% by weight and 1.5% by mixing the AA1050 material reference to the changes in the mechanical behavior of the tensile test is examined. Increase in tensile strength values of composite material was obtained by an average increase of 8.61% as a result of tensile analysis of samples taken at 3% nano SiO2 mixture without annealed rolled. The increase in the strength values of the material was found to be 4.42% increase as a result of tensile analysis of the samples taken at different thicknesses without annealing in 1.5% nano SiO2 mixture. The tensile strength values of the material increased by 3% nano SiO2 mixture without annealed and then annealed and made of H0 made of different thicknesses of samples taken as a result of the tensile analysis showed an average increase of 4.37%. The increase in the strength values of the material was obtained by an average of 3.99% as a result of the tensile analysis of the samples taken at different thicknesses of 1.5% nano SiO2 mixture and then annealed and made of H0. In the study, it was found that the optimum amount of SiO2 1.5% significantly increased the strength values of aluminum material.Keywords: Aluminum matrix nano SiO2 reinforced composite material, Nano SiO2, Nano composite material, Aluminum composit

Optimization study on surface roughness and tribological behavior of recycled cast iron reinforced bronze MMCs produced by hot pressing

Surface roughness reflects the quality of many operational parameters, namely service life, wear characteristics, working performance and tribological behavior of the produced part. Therefore, tribological performance is critical for the components used as tandem parts, especially for the MMCs (Metal Matrix Composites) which are a unique class of materials having extensive application areas such as aerospace, aeronautics, marine engineering and the defense industry. Current work covers the optimization study of production parameters for surface roughness and tribological indicators of newly produced cast iron reinforced bronze MMCs. In this context, two levels of temperature (400 and 450 °C), three levels of pressure (480, 640 and 820 MPa) and seven levels of reinforcement ratios (60/40, 70/30, 80/20, 90/10, 100/0 of GGG40/CuSn10, pure bronze-as received and pure cast iron-as received) are considered. According to the findings obtained by Taguchi’s signal-to-noise ratios, the reinforcement ratio has a dominant effect on surface roughness parameters (Ra and Rz), the coefficient of friction and the weight loss in different levels. In addition, 100/0 reinforced GGG40/CuSn10 gives minimum surface roughness, pure cast iron provides the best weight loss and pure bronze offers the desired coefficient of friction. The results showed the importance of material ingredients on mechanical properties by comparing a wide range of samples from starting the production phase, which provides a perspective for manufacturers to meet the market supply as per human requirements

Trim and Roll Reducing Systems Used in Yachts

One of the most wanted criteria for yachts and sightseeing boats is also comfort. However, the boats are expose to comfort and disturbing effects when sailing or in mooring due to the effects of wind and waves. In order to reduce these negative effects, various studies are being carried out and new systems are being developed to make yachts and boats more comfortable and safe. In this study, trim and roll reduce systems used in yachts and boats are introduced in general and information about which type of boats are compatible with each other is given and advantages and disadvantages of the systems are given

Cold plasma and microwave radiation applications on almond shell surface and its effects on the adsorption of Eriochrome Black T

Almond shell based adsorbents were thermally modified by cold plasma and microwave radiation for improving adsorption ability of Eriochrome Black T. The maximum adsorption capacities were 6.02, 18.18, and 29.41 mg/g for untreated, cold plasma and microwave radiation treated almond shell, respectively. The removal percentages of EBT compared with untreated almond shell were increased from 39.96% to 81.46% and 84.31% after modification by cold plasma and microwave radiation treatments, respectively. SEM, FT-IR spectroscopy and point of zero charge measurement were applied to analysis the almond shell surface. Data on equilibrium were evaluated by using Langmuir and Freundlich models

Equilibrium, kinetic and thermodynamic studies for dynamic adsorption of benzene in gas phase onto activated carbon produced from elaeagnus angustifolia seeds

Adsorption of pollutants onto activated carbon is very important in air purification systems. In this study, the dynamic adsorption of benzene in gas phase onto activated carbon which was produced from the elaeagnus angustifolia seeds, was investigated using a laboratory-scale continuous flow fixed-bed reactor system, under atmospheric pressure. The effects of the adsorption conditions such as activated carbon particle size (180–500 μm), nitrogen (N2) gas flow rate (0.050–0.120 L min−1) as the benzene in gas phase carrier, amount of activated carbon (0.10–0.75 g), concentration of benzene in gas phase at the inlet (9.95–14.85 ppm) and the adsorption temperature (293–323 K) on both the adsorption capacity and the adsorption efficiency were examined. Adsorption efficiency was achieved up to 100% under various adsorption conditions. Adsorption kinetics data were analyzed by using the Pseudo-First Order and Pseudo-Second Order kinetic models. Langmuir, Freundlich and Dubinin-Radushkevich models were used for the analysis of adsorption isotherms. The results showed that the Langmuir isotherm and Pseudo-Second Order models described the experimental data better when compared to other models. The maximum monolayer adsorption capacity (qmax) of activated carbon was determined to be 99.8 mg g−1 for 303 K. Thermodynamic analyzes indicated that the adsorption process of benzene in gas phase onto activated carbon was spontaneous (ΔG°<0), exothermic (ΔH°<0) and physical (ΔH°<20 kJ mol−1)

Fabrication and characterization of Fe3O4/perlite, Fe3O4/perlite@SiO2, and Fe3O4/perlite@SiO2@sulfanilamide magnetic nanomaterials

Abstract In this study, the fabrication of perlite-supported Fe3O4 (Fe3O4/perlite), SiO2-coated Fe3O4/perlite (Fe3O4/perlite@SiO2), and sulfanilamide-modified Fe3O4/perlite@SiO2 (Fe3O4/perlite@SiO2@sulfanilamide) magnetic nanomaterials and their characterization by various spectroscopic techniques were presented. For this purpose, first, Fe3O4/perlite was fabricated via the co-precipitation method. Then, Fe3O4/perlite@SiO2 and Fe3O4/perlite@SiO2@sulfanilamide nanomaterials were fabricated using the sol–gel method. The structural properties of the fabricated nanomaterials were characterized using Brunauer-Emmett-Teller (BET), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), SEM-energy-dispersive X-ray spectroscopy (EDX), thermogravimetric analysis-differential thermal analysis, and X-ray diffraction (XRD) analyses. The SEM, SEM–EDX, FTIR, and XRD analyses revealed that the fabrication and surface coatings of the Fe3O4/perlite, Fe3O4/perlite@SiO2, and Fe3O4/perlite@SiO2@sulfanilamide were successfully performed. It was concluded that the Fe3O4/perlite, Fe3O4/perlite@SiO2, and Fe3O4/perlite@SiO2@sulfanilamide showed a type IV-H3 hysteresis loop according to the International Union of Pure and Applied Chemistry classification. According to the BET analysis, it was found that the specific surface areas of the Fe3O4/perlite, Fe3O4/perlite@SiO2, and Fe3O4/perlite@SiO2@sulfanilamide were 8.09, 12.71, and 5.89 m2/g, respectively. The average pore radius of the Fe3O4/perlite, Fe3O4/perlite@SiO2, and Fe3O4/perlite@SiO2@sulfanilamide were 9.68, 7.91, and 34.69 nm, respectively, using the Barrett-Joyner-Halenda method. Moreover, the half-pore widths of the Fe3O4/perlite, Fe3O4/perlite@SiO2, and Fe3O4/perlite@SiO2@sulfanilamide were 2.27, 1.58, and 17.99 nm, respectively, using the density functional theory method. Furthermore, in light of characterization findings, the Fe3O4/perlite, Fe3O4/perlite@SiO2, and Fe3O4/perlite@SiO2@sulfanilamide were in crystalline cubic spinel form, and they had mechanical and thermal stability and a mesoporous structure. Within the framework of the results, these developed nanomaterials, which have potential in many applications, such as sustainable technologies and environmental safety technologies, were brought to the attention of related fields

Numerical evaluation on the effects of interceptor layout and blade heights for a prismatic planing hull

Planing hulls are exposed to effects such as trim and resistance that have a negative impact on their hydrodynamic performances. Interceptors are one of the systems to find solutions to reduce these negative effects. In this study, the effects of the interceptor layout and blade height on the hydrodynamic characteristics of a planing hull were investigated numerically, at varying speeds. The hydrodynamic behaviors of the interceptor at a selected case were also investigated in regular head waves. To reach this aim, a scaled prismatic planing hull form equipped with an interceptor which is suitable for planing vessels 4-10 m in length was selected for all analyses. The numerical study was performed by using the CFD (Computational Fluid Dynamics) approach which uses a finite volume method to discretize the RANS (Reynolds Averaged Navier Stokes) equations. The uncertainty of the numerical study was also performed to show the credibility of numerical results. According to the results of the current study, it is found that the most proper location of the interceptors for lower resistance is between the chine and the centerline of the selected planing hull. It is also understood that the effects of the blade height are directly related to the forward speed. Besides, the resistance values can be decreased by using interceptors up to FnB =2.5, while the presence of the interceptor has a negative effect on resistance after this speed regardless of the layout and selected blade height. In addition to this, the best interceptor blade heights for lower resistance at different forward speeds of the planing hull form were found for the tested cases. For the selected case, it is shown that interceptors are also useful in regular waves in terms of reducing dynamic trim, sinkage and resistance