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Farklı yüzey işlemlerinin Inconel 625 süper alaşım ve AISI 321 paslanmaz çelik üzerindeki çekme ve aşınma davranışlarına etkisi
No full textAISI 321 stainless steel and Inconel 625 superalloy are utilized in an extensive range of applications such as aircraft engines, nuclear powerplants and industrial furnaces due to their excellent mechanical properties at high temperatures. The surface treatment of these materials is necessary due to the extreme work ing environments. Boronizing and WC coating is the most important surface hard ening processes. In the current work, the effect of boronizing and WC coating on the wear performance and tensile behavior of AISI 321 and Inconel 625 at room and high temperature were investigated. Furthermore, damage mechanisms and fracture morphologies were observed using Scanning Electron Microscopy (SEM) and optical profilometry. According to room temperature tensile test results, yield strength (YS) and ultimate tensile strength (UTS) of the samples are reduced after the boronizing process. This strength reduction may be attributed to the softening of the material throughout the boronizing process at high temperature of 1100°C. On the other hand, ductility of the Inconel 625 samples has been decreased due to dynamic strain aging at 600°C. The yield strength of the boronized samples was significantly reduced because of the decomposition of boron particles throughout tensile test at elevated temperatures. Consequently, the fracture morphology observations revealed that the main fracture mechanism of both coated and uncoated conditions at high temperature was a ductile fracture represented by deep dimples. However, the boronized sample was drastically affected by grain growth during boronizing process and decomposition of dispersed particles. In contrast, the strain to failure of the WC coated sample was decreased due to the fast fracture of the ceramic WC layer at both room and high temperature tensile tests. Furthermore, results of SEM revealed that particle decomposition occured on the fracture surface of the boronized 321 stainless steel represented by dispersed boron particles on the edges of the dimples after failure at high temperature. Due to the high hardness and heat resistance of WC coated layer, the friction coefficient of the sample was higher than that of boronized and uncoated conditions at room tempearature. It was seen that the wear rates of boronized and WC coated AISI 321 were extremely lower than that of uncoated sample. On the other hand, at 600°C, WC coated wear rate was still lower but uncoated and boronized samples’ values were similar to the room temperature results. Inspection of room temperature the wear test results revealed that the wear rates of Inconel 625 uncoated and coated samples were similar to the results of AISI 321. WC coated samples’ wear rate was tremendously lower than the others. At high temperature, the boronized Inconel 625 had higher friction coefficient than the WC coated sample. A fluctuation was also noticed, which is linked to boron particle aggregation on the surface at high temperatures.AISI 321 paslanmaz ¸celik ve Inconel 625 s¨uper ala¸sımı, y¨uksek sıcaklıklardaki m¨ukemmel mekanik ¨ozelliklerinden dolayı u¸cak motorları, n¨ukleer santraller ve end¨ustriyel fırınlar gibi geni¸s bir uygulama yelpazesinde kullanılmaktadır. Zorlu ¸calı¸sma ko¸sulları nedeniyle, bu malzemeler ¨uzerine y¨uzey i¸slemleri uygu lamak bir gereksinim haline gelmi¸stir. Borlama ve Tungsten Karb¨ur (WC) kaplama en ¨onemli y¨uzey sertle¸stirme i¸slemlerindendir. Mevcut ¸calı¸smada, AISI 321 ve In conel 625’in oda sıcaklı˘gı ve y¨uksek sıcaklıktaki a¸sınma performansı ve ¸cekme davranı¸sı ¨uzerine borlama ve Tungsten Karb¨ur kaplamanın etkisi ara¸stırılmı¸stır. Ayrıca, Taramalı Elektron Mikroskobu (SEM) ve optik profilometri kullanılarak hasar mekanizmaları ve kırılma morfolojileri g¨ozlemlenmi¸stir. Oda sıcaklı˘gında ¸cekme testi sonu¸clarına g¨ore borlama i¸sleminden sonra nu munelerin akma dayanımı (YS) ve nihai ¸cekme dayanımı (UTS) azalmaktadır. Bu mukavemet azalması, 1100°C’lik y¨uksek sıcaklıkta borlama i¸slemi boyunca malzemenin yumu¸samasına ba˘glanabilir. Ote yandan Inconel 625 numunelerinin ¨ s¨unekli˘gi, 600°C’de dinamik gerinim ya¸slanması nedeniyle azalmı¸stır. Borlanmı¸s numunelerin akma mukavemeti, y¨uksek sıcaklıklarda ¸cekme testi boyunca bor par¸cacıklarının ayrı¸sması nedeniyle ¨onemli ¨ol¸c¨ude azalmı¸stır. Sonu¸c olarak, kırılma morfolojisi g¨ozlemleri, y¨uksek sıcaklıkta hem kaplamalı hem de kaplamasız ko¸sulların ana kırılma mekanizmasının, derin ¸cukurlarla temsil edilen s¨unek bir kırılma oldu˘gunu ortaya koymu¸stur. Bununla birlikte, borlanmı¸s numune, borlama i¸slemi sırasında tane b¨uy¨umesinden ve da˘gılmı¸s par¸cacıkların ayrı¸smasından b¨uy¨uk ¨ol¸c¨ude etk ilenmi¸stir. Buna kar¸sılık, seramik WC tabakasının hem oda sıcaklı˘gında hem de y¨uksek sıcaklıktaki ¸cekme testlerinde ani kırılması nedeniyle WC kaplı numunenin s¨unekli˘gi azalmı¸stır. Ayrıca, taramalı elektron mikroskobu sonu¸cları, y¨uksek sıcaklıkta kırılmadan sonra ¸cukurların kenarlarında da˘gılmı¸s bor par¸cacıkları g¨or¨ulen bor lanmı¸s 321 paslanmaz ¸celi˘gin kırılma y¨uzeyinde par¸cacık ayrı¸smasının meydana geldi˘gini ortaya koymu¸stur. WC tabakasının y¨uksek sertli˘gi ve ısı direnci nedeniyle, a¸sınma testinde WC kaplı AISI 321’in s¨urt¨unme katsayısı borlanmı¸s ve kaplamasız numunelere g¨ore daha y¨uksek ¸cıkmı¸stır. Borlanmı¸s ve WC kaplı AISI 321’in a¸sınma oranı, oda sıcaklı˘gında kaplanmamı¸s numuneden ¸cok daha d¨u¸s¨ukt¨ur. Ote yandan, 600 ¨ °C’de WC kaplı numunenin a¸sınma oranı hala d¨u¸s¨ukken kaplamasız ve borlanmı¸s nu munelerin de˘gerleri, y¨uzeyin delaminasyonu nedeniyle hemen hemen aynıdır. Inconel 625’in kaplanmamı¸s ve kaplanmı¸s numunelerin a¸sınma hızı davranı¸sı AISI 321’in sonu¸clarına benzerdir. WC kaplı numunelerin a¸sınma hızının di˘gerlerinden ¸cok daha d¨u¸s¨uk oldu˘gu g¨or¨ulm¨u¸st¨ur. Y¨uksek sıcaklıkta, borlanmı¸s Inconel 625, WC kaplı numuneden daha y¨uksek bir s¨urt¨unme katsayısına sahiptir. Y¨uksek sıcaklıktaki s¨urt¨unme katsayısı grafi˘ginde y¨uzeyde bor par¸cacıklarının birikimiyle ba˘glantılı bir dalgalanma g¨ozlenmi¸stir
A general-purpose protocol for multi-agent based explanations
No full textBuilding on prior works on explanation negotiation protocols, this paper proposes a general-purpose protocol for multi-agent systems where recommender agents may need to provide explanations for their recommendations. The protocol specifies the roles and responsibilities of the explainee and the explainer agent and the types of information that should be exchanged between them to ensure a clear and effective explanation. However, it does not prescribe any particular sort of recommendation or explanation, hence remaining agnostic w.r.t. such notions. Novelty lays in the extended support for both ordinary and contrastive explanations, as well as for the situation where no explanation is needed as none is requested by the explainee. Accordingly, we formally present and analyse the protocol, motivating its design and discussing its generality. We also discuss the reification of the protocol into a re-usable software library, namely PyXMas, which is meant to support developers willing to build explainable MAS leveraging our protocol. Finally, we discuss how custom notions of recommendation and explanation can be easily plugged into PyXMas.Chist-Era IV ; Ministero dell’Istruzione, dell’Università e della Ricerca ; TÜBİTA
Search for a vector-like quark T′ → tH via the diphoton decay mode of the Higgs boson in proton-proton collisions at √s = 13 TeV
No full textA search for the electroweak production of a vector-like quark T′, decaying to a top quark and a Higgs boson is presented. The search is based on a sample of proton-proton collision events recorded at the LHC at s = 13 TeV, corresponding to an integrated luminosity of 138 fb1. This is the first T′ search that exploits the Higgs boson decay to a pair of photons. For narrow isospin singlet T′ states with masses up to 1.1 TeV, the excellent diphoton invariant mass resolution of 1–2% results in an increased sensitivity compared to previous searches based on the same production mechanism. The electroweak production of a T′ quark with mass up to 960 GeV is excluded at 95% confidence level, assuming a coupling strength κT = 0.25 and a relative decay width Γ/MT′ < 5%. [Figure not available: see fulltext.].BMBWF and FWF (Austria); FNRS and FWO
(Belgium); CNPq, CAPES, FAPERJ, FAPERGS, and FAPESP (Brazil); MES and BNSF
(Bulgaria); CERN; CAS, MoST, and NSFC (China); MINCIENCIAS (Colombia); MSES
and CSF (Croatia); RIF (Cyprus); SENESCYT (Ecuador); MoER, ERC PUT and ERDF
(Estonia); Academy of Finland, MEC, and HIP (Finland); CEA and CNRS/IN2P3 (France);
BMBF, DFG, and HGF (Germany); GSRI (Greece); NKFIH (Hungary); DAE and DST
(India); IPM (Iran); SFI (Ireland); INFN (Italy); MSIP and NRF (Republic of Korea); MES
(Latvia); LAS (Lithuania); MOE and UM (Malaysia); BUAP, CINVESTAV, CONACYT,
LNS, SEP, and UASLP-FAI (Mexico); MOS (Montenegro); MBIE (New Zealand); PAEC
(Pakistan); MES and NSC (Poland); FCT (Portugal); MESTD (Serbia); MCIN/AEI and
PCTI (Spain); MOSTR (Sri Lanka); Swiss Funding Agencies (Switzerland); MST (Taipei);
MHESI and NSTDA (Thailand); TUBITAK and TENMAK (Turkey); NASU (Ukraine);
STFC (United Kingdom); DOE and NSF (U.S.A.).
Individuals 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, 884104, and COST Action CA16108 (European Union); the Leventis
Foundation; the Alfred P. Sloan Foundation; the Alexander von Humboldt Foundation;
the Belgian Federal Science Policy Office; the Fonds pour la Formation à 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; the Ministry of Education, Youth and
Sports (MEYS) of the Czech Republic; the Hellenic Foundation for Research and Innovation
(HFRI), Project Number 2288 (Greece); the Deutsche Forschungsgemeinschaft (DFG), under
Germany’s Excellence Strategy — EXC 2121 “Quantum Universe” — 390833306, and under
project number 400140256 — GRK2497; the Hungarian Academy of Sciences, the New
National Excellence Program — ÚNKP, 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; 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 Fundação para a Ciência
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 Investigación
Científica y Técnica de Excelencia María 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 B05F650021 (Thailand); the Kavli Foundation; the Nvidia
Corporation; the SuperMicro Corporation; the Welch Foundation, contract C-1845; and the
Weston Havens Foundation (U.S.A.Publisher versio
İki frekans bandinda farklı polarizasyon tiplerinde çalısan vivaldi anten tasarımı
No full textThis thesis presents a novel dual-polarized antenna design based on two orthogonally place Vivaldi antenna elements and are driven by a specially designed feeding network that splits incoming signal into two wherein one of them is linearly polarized between 4 and 6 GHz and the other one is circularly polarized from 14.5 to 15.5 GHz. Splitting of input signal into the two frequency bands, a diplexer is designed. A wilkinson power divider and a transmission-line phase shifter are employed to realize phase difference to achieve circular polarization at the upper frequency band. The feed network is integrated with the Vivaldi elements to ensure a compact form factor critical for reflector applications. In order to avoid crossing of two microstrip-to-slotline transition of the two Vivaldi elements, a small shift between them is introduced. This antenna is intended to be used as a feed antenna for reflector systems employed in radio link systems of drones. Combination of these distinct frequency bands with different polarization requirements allows use of single ground control antenna instead of two independent antennas thereby reducing cost and space requirements. For demonstration purpose, a prototype is fabricated. The antenna achieves better than -15 dB input reflection coefficients over most of the operating bands and axial ratio is less than 2 dB for the upper frequency range. The antenna exhibits gain between 7.2 to 9.5 dBi from 4 to 16 GHz. Meanwhile, stable radiation patterns are achieved with the cross polarization lower than -25 dB across the operating bands at boresight direction.Bu tez çalışmasında, içiçe geçirilmiş iki Vivaldi antenin tasarımı ve anten tarafından gelen/gönderilen sinyali bölüp iki farklı polarizasyon türü ( 4 ile 6 GHz arasinda çizgisel polarizasyon ve 14,5 ile 15,5 GHz aralığında dairesel polarizasyon) elde etmek için özelle tasarlanmış beslenme ağı tasarimi sunulmuştur. Giriş sinyalinin iki frekans bandına bölmek için dipleks kullanıldı. Üst frekans bandında dairesel polarizasyon elde etmek için Wilkinson güç bölücü ve faz dönüştürücü ( açı farkını yakalamak için) tasarlandı. Beslenme ağı reflektör uygulamaları için kritik olan kompakt bir form sağlamak amacıyla Vivaldi antenleriyle entegre edilmiştir. Bu anten drone'ların radyo link sistemlerinde kullanılan reflektör sistemleri için besleme anteni olarak kullanılmak üzere tasarlanmıştır. Bu anten farklı frekans bantlarının farklı polarizasyon gereksinimlerinin birleştirilmesi, iki bağımsız anten yerine tek yer kontrol anteninin kullanılmasına izin vermektedir. Bu şekilde maliyet ve alan gereksinimlerini azaltılmış olacaktır. Bu antenin bir prototip üretilmiştir. Antenin yansıma katsayıları, çalışma bantlarının çoğunda -15 dB'den daha iyi bir sonuç sunmaktadır. Üst frekans aralığı için de eksenel oran 2 dB'den azdır. Anten 4-6 GHz ve 14-16 GHz bantları arasında 7,2 ile 9,5 dBi arasında kazanç sergilemektedir. Bu arada, dar görüş yönünde çalışma bantları boyunca -25 dB'den daha düşük çapraz polarizasyon ile istikrarlı radyasyon desenleri elde edilmektedir
Buzdolabı kablo tasarımının bozulma gücü testine deneysel etki analizi
No full textThe ever-increasing variety of electronic products brings with it many tests and controls. Especially for a product such as a refrigerator, which has an important place in the lives of users and works non-stop for almost its entire life, all compatibility tests that may affect the end-user must be carried out. Electromagnetic compatibility (EMC) tests are the most critical of these tests. In this study, the effect of the disturbance power test, one of the EMC tests, on the changing properties of the product was investigated. The effect of three different cable structures used in the refrigerator on the disturbance power test was investigated. These tests are carried out to cover 10 different frequencies in three products using different cable structures. Tables containing the oscilloscope results of these tests and the margin values corresponding to the frequencies are included in the document. In addition, visuals containing the differences between each cable structure and cable have been added. The results and analyzes of these tests are included in this thesis.Her geçen gün artan elektronik ürün çeşitliliği birçok test ve kontrolü de beraberinde getirmektedir. Özellikle buzdolabı gibi kullanıcıların hayatında büyük bir yeri olan ve neredeyse tüm ömrü boyunca hiç durmadan çalışan bir ürün için son kullanıcıyı etkileyebilecek tüm uyumluluk testleri yapılmalıdır. Elektromanyetik uyumluluk (EMC) testleri bu testlerin en kritik olanıdır. Bu çalışmada, EMC testlerinden biri olan bozucu güç testinin ürünün değişen özelliklerine etkisi araştırılmıştır. Buzdolabında kullanılan üç farklı kablo yapısının bozucu güç testine etkisi araştırılmıştır. Bu testler, farklı kablo yapıları kullanılarak üç üründe 10 farklı frekansı kapsayacak şekilde gerçekleştirilmektedir. Bu testlerin osiloskop sonuçlarını ve frekanslara karşılık gelen marjin değerlerini içeren tablolar doküman içerisinde yer almaktadır. Ayrıca her bir kablo yapısı ve kablolar arasındaki farkları içeren görseller eklenmiştir. Bu testlerin sonuçları ve analizleri tezde yer almaktadır
Multi-plant manufacturing assortment planning in the presence of transshipments
No full textIn this study, we consider the assortment planning problem of a manufacturing firm with multiple plants. Making a plant capable of producing a product is costly, therefore the firm cannot manufacture every product in every plant. In case a customer's order in a particular region is not available in the closest plant, another plant can ship the product using transshipment, but at an extra transportation cost. If a demanded product is not produced in any plant, substitution from first choice to a second choice is also considered, which can be either satisfied by the closest plant, or by transshipment. The problem is to jointly determine assortments in all plants such that total profit after assortment and transshipment costs is maximized. The resulting problem is complex as transshipments and substitutions are intertwined to affect assortment decisions. We show that the optimal assortments are nested, i.e., the assortment of a plant with a smaller market share is a subset of the assortment of a plant with a larger share. The common assortment of all locations is shown to be in the popular set (i.e., no leapfrogging in product popularities), and a sufficient condition on substitution rate is derived for each individual assortment to be in the popular set. We conduct an extensive numerical study to understand the effects of allowing transshipments on resulting assortments. Moreover, we introduce approximate assortment planning algorithms that benefit from the derived structural properties, which are shown to generate near-optimal assortments in a broad range of instances tested.TÜBİTA
Offloading deep learning powered vision tasks from UAV to 5G edge server with denoising
No full textOffloading computationally heavy tasks from an unmanned aerial vehicle (UAV) to a remote server helps improve battery life and can help reduce resource requirements. Deep learning based state-of-the-art computer vision tasks, such as object segmentation and detection, are computationally heavy algorithms, requiring large memory and computing power. Many UAVs are using (pretrained) off-the-shelf versions of such algorithms. Offloading such power-hungry algorithms to a remote server could help UAVs save power significantly. However, deep learning based algorithms are susceptible to noise, and a wireless communication system, by its nature, introduces noise to the original signal. When the signal represents an image, noise affects the image. There has not been much work studying the effect of the noise introduced by the communication system on pretrained deep networks. In this work, we first analyze how reliable it is to offload deep learning based computer vision tasks (including both object segmentation and detection) by focusing on the effect of various parameters of a 5G wireless communication system on the transmitted image and demonstrate how the introduced noise of the used 5G system reduces the performance of the offloaded deep learning task. Then solutions are introduced to eliminate (or reduce) the negative effect of the noise. Proposed framework starts with introducing many classical techniques as alternative solutions, and then introduces a novel deep learning based solution to denoise the given noisy input image. The performance of various denoising algorithms on offloading both object segmentation and object detection tasks are compared. Our proposed deep transformer-based denoiser algorithm (NR-Net) yields state-of-the-art results in our experiments
Reversing image signal processors by reverse style transferring
No full textRAW image datasets are more suitable than the standard RGB image datasets for the ill-posed inverse problems in low-level vision, but not common in the literature. There are also a few studies to focus on mapping sRGB images to RAW format. Mapping from sRGB to RAW format could be a relevant domain for reverse style transferring since the task is an ill-posed reversing problem. In this study, we seek an answer to the question: Can the ISP operations be modeled as the style factor in an end-to-end learning pipeline? To investigate this idea, we propose a novel architecture, namely RST-ISP-Net, for learning to reverse the ISP operations with the help of adaptive feature normalization. We formulate this problem as a reverse style transferring and mostly follow the practice used in the prior work. We have participated in the AIM Reversed ISP challenge with our proposed architecture. Results indicate that the idea of modeling disruptive or modifying factors as style is still valid, but further improvements are required to be competitive in such a challenge
Analysis of communication distance and energy harvesting for vehicular VLC using commercial taillights
No full textThis paper presents an investigation into the communication range and energy harvesting capabilities of a vehicle-to-vehicle (V2V) visible light communication (VLC) system that utilizes commercial taillights (TLs) as wireless transmitters and a single photodetector (PD) as the wireless receiver. First, We derived a closed-form expression for the distance and the harvested energy using realistic ray-tracing channel models that consider the asymmetrical pattern of commercial car taillights. Then, analyze the impact of various transceivers and system parameters on the overall performance of the V2V VLC system. Our findings demonstrated that the proposed V2V VLC system could achieve a communication range of more than 50 m at a BER threshold of 10-3 for low data rate applications (i.e., safety) and more than 30 m for higher data rate application at same BER target. Our results further reveal that an energy harvesting of 4.5 mJ can be achieved when the BER performance is kept at 10-6, making it a promising solution for low-power wireless communication in V2V VLC scenarios. Moreover, the results have shown that the harvested energy can be affected by parameters such as the BER, bandwidth, and electrical transmitting power, which emphasizes the importance of optimizing these parameters for optimal harvesting energy. Overall, this paper provides valuable insights into the potential of V2V VLC systems for energy-efficient communication in vehicular communicationsUniversitetet i Troms