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Nozul geometrisinin MQL ve hava soğutma sistemlerindeki yüzey soğutma performansına etkisi
(UTIS Organizing Committee, 2025-10-02) Özkan, Şule; Göktaş, Anıl Gökhan; Kuzu, Ali Taner; Saklakoğlu, İ. Etem
Bu çalışmada, talaşlı imalatta sürdürülebilir soğutma–yağlama uygulamalarına yönelik olarak dört farklı nozul tasarımının soğutma performansı incelenmiştir. Karbon çelik plaka 90 °C’ye ısıtılmış ve üç farklı ortamda (MQL, basınçlı hava, CO₂) soğutulmuştur. Sıcaklık verileri, plaka üzerinde üç noktaya yerleştirilen K tipi termokupllarla kaydedilmiş ve 90 °C’den 50 °C’ye düşüş süresi performans kriteri olarak kullanılmıştır. Bulgular, MQL’de dar çıkış çaplı nozulların merkez bölgelerde, hava ve CO₂’de ise geniş çıkış çaplı nozulların daha yüksek soğutma etkinliği sağladığını göstermiştir. En kısa soğuma süreleri CO₂ ile elde edilmiş, MQL ise sınırlı soğutma kapasitesiyle en uzun süreleri vermiştir. Sonuç olarak, nozul geometrisinin ve akışkan türünün soğutma performansını belirleyen kritik faktörler olduğu ortaya konmuştur.
Enhancement of epoxy properties through graphene nanofillers produced in molten salt: morphological, thermal and mechanical characterization
(Springer, 2026) Gül, Ayşenur; Kamali, Ali Reza
This research investigates the enhancement of epoxy resin properties through the incorporation of graphene nanoplatelets (GNPs), synthesized via the molten salt exfoliation method, as nanofillers. The study evaluates the morphology, thermal conductivity, and mechanical performance of the resulting nanocomposites. Electron microscopy reveals a high density of reactive edge sites in the graphene material, which enable bonding with epoxy groups during curing. It also shows a uniform dispersion of graphene nanoplatelets (GNPs) within the epoxy matrix, leading to reduced void formation and enhanced interfacial bonding. A notable improvement in the physical and mechanical properties of the epoxy was observed with the addition of GNPs up to 1.0 wt%. At this concentration, Young’s modulus increased by approximately 42% (from 2.9 to 4.2 GPa), while thermal conductivity, compressive strength, and tensile strength improved by around 41%, 9%, and 32%, respectively. These findings indicate that the integration of GNPs into epoxy resin significantly enhances both thermal and mechanical performance, positioning the nanocomposites as strong candidates for advanced structural applications.
Investigation of process parameters in rotary swaging
(TICMET, 2023-11-16) Bakkal, Mustafa; Karagüzel, Umut; Kuzu, Ali Taner; Kurt, Hasan Aytuğ; Çakır, Hasan
Rotary swaging is a metalworking process used to reduce the diameter of a cylindrical workpiece or to shape it into a desired form. It is a cold-forming process, meaning it is carried out at room temperature or slightly elevated temperatures without the need for additional heat. Rotary swaging is particularly useful for creating components with a taper or complex geometries. In this study, focusing on an effects of die angle and feeding rate upon specified tubular geometry which have 2 mm thickness. An identified load was applied to the tubular geometry in Simufact finite element software for 3 different die angles and feed rates. As a result, optimum die angle and feed rate were determined.
Effects of different production parameters on mechanical properties in FDM-printed products
(Eklemeli İmalat Derneği Yayınları, 2022-10-08) Kösemen, Elifnur; Kuzu, Ali Taner; Bakkal, Mustafa
FDM, which is a common additive manufacturing technology in producing plastic parts, allows for the comparison of many different production parameters. This article presents the variation of density, hardness, tensile and impact strength depending on the production parameters of the number of contours, infill pattern and orientation angle. 8 different production parameter combinations were created using 2 diff erent contour numbers as 1 and 2, 2 different infill patterns as sparse high density and hexagram, and two different orientation angles as 0o/45o degrees, and sample production was made with FDM technology and ABS material. In the experiments performed on the samples produced with the specified production combinations, no major change in density and hardness was detected, and it was determined that the production parameter combination that gave the best results in both tensile and impact strength was hexagram infill pattern, 45o orientation angle and 2 contour production parameters.
Zirkonyum esaslı kalın camsı metalin taşlanmasında kesme sıcaklıkları ve enerji paylaşımı
(UTIS Organizing Committee, 2017-11-02) Timur, Azmi; Karipçin, İlker; Karagüzel, Umut; Kuzu, Ali Taner; Bakkal, Mustafa
Bu çalışmada talaşlı imalat işlemleri arasında özgül enerjinin en yüksek olduğu ve ısıyla ilgili problemlerin en çok yaşandığı “taşlama” işleminin farklı taş ve işleme parametrelerinin zirkonyum esaslı Kalın Camsı Metal’nin [KCM] amorf yapısına metalürjik etkileri, meydana gelen taşlama sıcaklıkları, enerjinin ne kadarının KCM’ye geçtiği araştırılmıştır. Seçilen alaşım Vitreloy 105 ticari ismine sahip ve Zr52,5Ti5Cu17,9Ni14,6Al10 bileşimindeki Zr-esaslı KCM’dir. 6.35 mm çapa sahip dairesel kesitli Zr-esaslı KCM çubukların yüzey ve yüzey altı sıcaklıkları gömme termokupl yöntemi ile ölçülmüş ve ardından içyapı Xışını difraksiyonu ile analiz edilmiştir. Bunların yanında iş parçasına ısı şeklinde geçen enerjinin taşlama sırasında harcanan toplam enerjiye oranı olarak ifade edilen enerji paylaşımı hesaplanmıştır. Bu hesaplarda kullanılmak üzere kuvvet ölçümü de yapılmıştır. İlerleme hızı ve paso kalınlığı sabit tutularak farklı kesme hızında taşlama testleri yapılmıştır. Sabit kesme hızı ve paso kalınlığında ve farklı ilerleme hızında yapılan testlerde sıcaklıkların değişimi farklı bir eğilim göstermiştir. Daha sonra kesme hızı ve ilerleme hızı sabit tutulup paso kalınlığı arttırılmıştır. Bütün bu deneylerde CBN aşındırıcılı taş kullanılırken, aşındırıcı malzemesinin sıcaklıklara olan etkisini görebilmek için son olarak CBN yerine Al2O3 aşındırıcılı taş kullanılarak bir test daha yapılmıştır. Bütün taşlanan numunelerde X-ışını difraksiyonu analizi yapılarak kristalleşme olup olmadığı belirlenmiş ve sonuçlar ölçülen sıcaklıklarla ilişkilendirilmiştir. Son olarak bütün testler için enerji paylaşımı değerleri hesaplanmıştır ve bu değerlerin kesme parametreleri ve aşındırıcı malzemesiyle değişimi incelenmiştir.
Effect of cutting strategy on machining of thin walled polymer
(UTIS Organizing Committee, 2017-11-02) Keklik, Burak Taha; Kuzu, Ali Taner; Başçı, Ümit Gencay; Karagüzel, Umut; Kayıhan, Mete; Bakkal, Mustafa
This paper presents the effect of tool path on machining of thin walled thermoplastic polymer, ABS. The effects of cutting speed, feed rate and tool path are studied to evaluate surface quality on thin walled parts. Four different cutting pattern (“zig”, “zig-zag”, “follow periphery” and “trochoidal”) with uncoated WC tool were investigated in the cutting tests. The quality of grooves was examined by their surface roughness, dimensional accuracy and burr structure. Experiments show that the down-milling and “follow periphery” creates dimensionally more accurate grooves. Average 4 μm surface roughness and discontinuous chip formation is obtained in up-milling process. According to the study, the better surface quality and dimensional accuracy can be achieved by down milling in “zig-zag” pattern in terms of surface roughness.
Development of turn-milling machine tool program parameters based on basic cutting geometry
(2017-11-02) Berenji, Kaveh Rahimzadeh; Karagüzel, Umut; Özlü, Emre; Budak, Erhan
The turn-milling operation is a multitasking machining process that takes advantages of turning and milling operations simultaneously. However, using these two machining operations at the same time results in more complex and different cutting parameters compared to conventional turning process. In this study, the turnmilling kinematics have been modeled analytically. Using the model proposed in this study, the required parameters for a machine tool such as feed rate, workpiece, and tool rotational speed can be derived in terms of basic cutting parameters which are cutting speed, feed per tooth, radial depth of cut, and axial depth of cut.
Material replacement and topology optimization study on a PVC cutting machine component
(TICMET Organizing Committee, 2011-11-03) Hançerkıran, Zeynep; Ahlatcı, Umut Can; Topuzoğlu, Ertan; Kasapcopur, Taylan; Alkan, Erkan; Ertürk, Fikret; Karagüzel, Umut; Bakkal, Mustafa
In this study, it is aimed to lighten the aluminum body of the PVC cutting machine, reduce the production cost and shorten the production time. With this purpose, firstly, literature researches of composite materials were made and the PVC machine was introduced. Then, alternative designs of this body were made in Fusion360, and material selection was discussed in line with the analyzes made on the designs in ANSYS. Designs of this body were reexamined by topology optimization of designs created with selected materials. Test and analyzes are shown step-by-step in order to achieve the final result with the necessary changes to mitigate. As a result the body part has lightened up to %70 with the choice of different materials and design.
Experimental and analytical investigation of drilling in high performance hybrid composites
(2019-11-09) Kayıhan, Mete; Karagüzel, Umut; Bakkal, Mustafa
Hybrid composites produced by the addition of metal alloys to carbon fiber reinforced composites (CFRP) have superior mechanical and physical properties, excellent specific strength and high resistance to corrosion. The most commonly used machining processes in the use of hybrid materials in industry is the drilling process. After the drilling processes, due to the anisotropic properties of the CFRP material, delamination, uncut fiber and fiber pullout are observed. For this reason, the performance of CFRP after drilling operation must be the main concern. Therefore, in this study, hybrid materials were tested on factors such as stack order, drilling speed and feed rate which should be applied in hole drilling process and analysis were made on various results. The tests were performed with three-factor and three-level L9 Taguchi orthogonal experiment design due to minimize the cost and material. As a result of this study, the best stack order and drilling parameters of the hybrid composite materials was determined with many variables such as force and torque values, the required energy, surface roughness values and delamination factors.
Investigation and prediction of surface integrity induced by milling of hot forged and heat treated AA7075
(Motto, 2024-11-03) Tok, Görkem; Dinçer, Ammar Tarık; Kuzu, Ali Taner; Bakkal, Mustafa; Saklakoğlu, İ. Etem
This study examines the influence of cutting parameters on surface integrity, focusing on residual stress and surface roughness, in hot-forged and T6 heat-treated AA7075 components post-milling. Using the Taguchi L9 DOE method, orthogonal cutting milling experiments were performed, with residual stress measured via nondestructive X-ray diffraction (XRD). The analysis indicated that lower cutting speeds reduce residual stress, with down milling causing compressive and up milling causing tensile stresses. A proposed model showed a significant correlation between cutting force and residual stress—higher cutting forces increased residual stress. Surface roughness assessment revealed that feed rate greatly impacts residual stress, with lower feed rates reducing roughness. These insights will aid in developing a regression model for predicting outcomes in future experiments, enhancing the understanding and control of surface integrity in milling AA7075 components.
Dairesel testere makine parametrelerinin yüzey kalitesine etkisi incelenmesi
(Motto, 2024-11-03) Çakır, Hasan; Yılmaz, Mahmut; Yeter, Alper; Karagüzel, Umut; Kuzu, Ali Taner; Bakkal, Mustafa; Saklakoğlu, İ. Etem
Dairesel testere ile yapılan kesimlerde gelişen teknolojiyle birlikte kesilen yüzeylerde yüksek yüzey kalitesi beklentisi artmıştır. Yüzey kalitesine kesme işleme sırasında kullanılan dairesel testere ve testere malzeme yapısı doğrudan etki etmektedir. Aynı zamanda makine çalışma parametreleri de yüzey kalitesine etki etmektedir. Yapılan bu çalışmada makine çalışma parametreleri içersinde yer alan ilerleme ve kesme hızlarında, farklı değerler kullanılarak kesme deneyleri yapılmıştır. Deneyler veri toplama cihazı ile makine gövdesi üzerine yerleştirilen ivmeölçer sensörlerden titreşim verileri toplanmıştır. Toplanan veriler, veri toplama cihazı arayüz programında işlenerek maksimum ivme değerleri ve ivmelerin ortalama karekök değerleri hesaplanmıştır. Hesaplanan veriler ile krest faktörünün farklı ilerleme ve kesim hızlarında değeri bulunmuştur. Yüzey pürüzlülük ölçüm cihazı kullanılarak kesim yapılan parçaların yüzey pürüzlülük değeri tespit edilmiştir. Deneyler sonucunda makinede meydana gelen titreşimlerin yüzey pürüzlülüğüne olan etkisi araştırılmıştır.
Dogu Anadolu Gözlemevi (DAG) integrated dome and telescope on-site assembly
(SPIE, 2024) Marchiori, Gianpietro; Rampini, Francesco; Amalfi, Manfredi; Bressan, Riccardo; Ghedin, Leonardo; Battistel, Cristina; Manfrin, Cristiana; Vio, L.; Niero, Tiziano; Marchiori, Tommaso; Pirnay, Olivier; Gabriel, Eric; Méant, Laurence; Yeşilyaprak, Cahit; Keskin, Onur
The Dogu Anadolu Gözlemevi (DAG) Eastern Anatolia Observatory is an astronomical project fully funded by Turkish Ministry of Development and the Atatürk University of Astrophysics Research Telescope (ATASAM). DAG Observatory will be provided with a 4m-class optical and infrared telescope, equipped with secondary (0.76m) and tertiary mirrors which furnish the telescope with two Nasmyth foci. Since 2015, the project has seen the crucial contribution of EIE GROUP in the Design, Production and on-site Installation of the 4m class optical/near-infrared telescope (DAG Telescope) in contract with AMOS company. EIE GROUP is also the main contractor of the 18.6m-diameter Rotating Building (DAG Dome) at an altitude of 3170m asl on the Erzurum Plateau, Turkey. The telescope was completely pre-assembled and successfully tested at the Integration Area Facilities of the EIE GROUP. Subsequently disassembled and transported to the final installation site. Despite the serious effects of the pandemic, the EIE GROUP, in agreement with its final Customer, has adopted a telescope assembly strategy integrated with the final assembly phases of the Dome. This allowed EIE to mount the entire telescope, in a single summer season, in total safety (thanks to the special measures adopted). This paper focuses on the development of this on-site assembly EIE activities of DAG Telescope, which at present have exceeded the 95% of completion. The main critical issues and related engineering solutions will be analyzed, with emphasis on both managerial and erection approaches adopted by EIE GROUP for this integrated phase of the project completion.
DAG rotating enclosure final erection and acceptance tests
(SPIE, 2024) Marchiori, Gianpietro; Rampini, Francesco; Amalfi, Manfredi; Bressan, Riccardo; Ghedin, Leonardo; Battistel, Cristina; Manfrin, Cristiana; Vio, L.; Niero, Tiziano; Marchiori, Tommaso; Yeşilyaprak, Cahit; Keskin, Onur
The DAG (Dogu Anadolu Gözlemevi) observatory is the largest observatory in Turkey and is composed by the 4m-class infrared Telescope, the Rotating Enclosure, the dome fixed structure and the auxiliary building. It is mounted on the top of Karakaya Mountain at 3170m altitude, close to Erzurum, in Turkey. This presentation refers to the DAG Rotating Enclosure. The Rotating Enclosure is octagonal sized steel structure with eight trolleys acting on a rai of 18.6 meters diameter. The structure is and 14.5m high over a pillar 9.0m. It is equipped with an observing slit door composed by two L-Shaped elements. Six sliding ventilation doors, about 3.7x6.5m each, that can be opened independently and with different degrees of aperture allow for optimizing the internal airflow. Immediately Inside the observing slit doors, there is a windscreen consisting of 3 panels that, in case of wind, are raised in accordance with the telescope elevation to protect it. The panels have a specific degree of air permeability to still allow ventilation for the telescope. A 6.5tons overall bridge crane allows to move pieces in every zone of the rotating enclosure for the maintenance of the telescope optics. At the beginning of November 2023, EIE carried out all acceptance tests with the end customer and delivered the rotating enclosure to ATASAM. This paper provides the results of the final erection and reports the procedures and results of the Acceptance Tests performed by EIE for the DAG Rotating Enclosure activities. 4m class telescopes and related Domes represent nowadays a consolidated part of EIE core-business, a low costs standard product able to satisfy the most critical observational requirements of astronomers.
DAG telescope first light commissioning status
(SPIE, 2024) Yeşilyaprak, Cahit; Keskin, Onur; Güçsav, Bülent; Öztürk Cetni, Derya; Kuruçolak, Mehmet
DAG, the 4-meter VIS/NIR telescope and the observatory, reached foreseen first light status at last: the enclosure acceptance is completed; to finalize the opto-mechanical alignment and pointing/tracking, the telescope mirrors have been exposed to heavens in absence of instrumentation. On the optical train; the two instruments that make the telescope distinctive, namely KORAY (the optical derotator) and flexible concept TROIA (ExAO) systems are characterized at the laboratory, and are anxiously waiting to be installed at their blessed location of mission - the diffraction limited Nasmyth platform along with the PLACID stellar coronagraph and DIRAC (NIR camera). We felt that PLACID, which is not yet lead star got jealous; so with the funding provided by the RACE-GO (ERC Project), within just after 60 days of its first mission, it will undergo for a technical makeover to a K-Band instrument. We now have a dilemma, the vacant seeing Nasmyth platform - the landlord- is still waiting for a cutting-edge tenant. Thus, the paper not only presents the telescope and its instrumentation, but also reserves a dedicated section for possible co-operations/collaborations to take place on the seeing Nasmyth platform.
DAG (Dogu Anadolu Gozlemevi) telescope mount performances
(SPIE, 2024) Marchiori, Gianpietro; Rampini, Francesco; Amalfi, Manfredi; Bressan, Riccardo; Ghedin, Leonardo; Battistel, Cristina; Manfrin, Cristiana; Vio, L.; Niero, Tiziano; Marchiori, Tommaso; Pirnay, Olivier; Gabriel, Eric; Méant, Laurence; Yeşilyaprak, Cahit; Keskin, Onur
The DAG (Dogu Anadolu Gözlemevi) Eastern Anatolia Observatory is an astronomical project fully funded by Turkish Ministry of Development and the Atatürk University of Astrophysics Research Telescope (ATASAM). DAG Observatory is provided with a 4m-class optical and infrared telescope, equipped with secondary (0.76m) and tertiary mirrors which furnish the telescope with two Nasmyth foci. Since 2015, the project has seen the crucial contribution of EIE GROUP in the Design, Production and on-site Installation of the mount structure of the 4m class optical/near-infrared telescope (DAG Telescope) in contract with AMOS company. EIE GROUP is also the main contractor of the 18.6m-diameter Rotating Building (DAG Dome) at an altitude of 3170m asl on the Erzurum Plateau, Turkey. After completing a full assembly and testing in the factory, the telescope was subsequently disassembled and transported to the final installation site. Now, on-site assembly activities have been completed, and all internal acceptance tests regarding the mount structure have been conducted. This document focuses on the on-site assembly activities of the EIE Group, as well as the related internal pre-commissioning, commissioning, and functional and acceptance tests.
Assessing dyslexia with machine learning: a pilot study utilizing Google ML Kit
(IEEE, 2023-12-19) Eroğlu, Günet; Harb, Mhd Raja Abou
In this study, we explore the application of Google ML Kit, a machine learning development kit, for dyslexia detection in the Turkish language. We collected face-tracking data from two groups: 49 dyslexic children and 22 typically developing children. Using Google ML Kit and other machine learning algorithms based on eye-tracking data, we compared their performance in dyslexia detection. Our findings reveal that Google ML Kit achieved the highest accuracy among the tested methods. This study underscores the potential of machine learning-based dyslexia detection and its practicality in academic and clinical settings.
Optimum torque distribution during regenerative braking in a fully electrical vehicle via dynamic programming
(IEEE, 2023-10-28) Ergün, Ömer; Çaycı, N. Okan; Dinçmen, Erkin; İstif, İlyas
In electric vehicles, it is important to maximize their regenerative braking performances for obtaining longer driving distances. In this study, for an electric vehicle having motors on the front and rear axles, an optimum torque distribution algorithm based on dynamic programming method is proposed for maximizing the regenerative braking energy. Electric motor limits, efficiency maps, battery model and braking force constraints given in the European regulations are considered in the proposed algorithm. The dynamic programming algorithm code and simulation studies for different braking scenarios are carried out via MATLAB. Simulation studies show that via the proposed torque distribution algorithm, significant improvements in the regenerated braking energy are obtained with respect to the fixed-rate torque distribution algorithm.
Eastern Anatolia Observatory (DAG): recent development in 2019
(Universidad Nacional Autonoma de Mexico, 2019-10-04) Yeşilyaprak, Cahit; Keskin, Onur
Eastern Anatolia Observatory (DAG) will be the Turkey’s largest (4m) and first infrared observatory is located in Erzurum city at the East part of Turkey with an altitude of 3170 m. We present the recent development of DAG until the end of September in 2019.
Wind disturbance cancellation for smaller alt-azimuth telescopes
(Universidad Nacional Autonoma de Mexico, 2019-10) Ünal, Ali Cem; Kararsız, Gökhan; Yılmaz, Cemal Tuğrul; Keskin, Onur; Yeşilyaprak, Cahit
This study focuses on eliminating unknown amplitude wind disturbance for 2-DOF alt-azimuth configuration small telescopes. An adaptive controller is designed to overcome wind disturbance as a set and forget system. The mathematical model is derived based on 2-DOF alt-azimuth configuration. The wind disturbance is modeled as a sum of sinusoidal with unknown amplitude, frequency and phase by using Wind-Gust model. The controller aims to cancel the effect of the disturbance on the altitude and azimuth angles of the telescope while positioning or staying static on a dedicated configuration. The asymptotic stability is proven with the Lyapunov approach. The numerical study is illustrated to success of the proposed controller.
TROIA Adaptive optics system for DAG telescope; assembly and laboratory performance prior to on-sky assessment
(SPIE, 2022-08-29) Keskin, Onur; Jolissaint, Laurent; Bouxin, Audrey; Yeşilyaprak, Cahit
In this article, we describe the current status of the development of TROIA* a pyramid wavefront sensor based adaptive optics system designed for DAG, a new 4 m telescope located in Eastern Anatolia, Turkey. The wavefront uses a no-noise electron-multiplied CCD camera, and the deformable mirror has a large actuators density, allowing coronagraphic science in one hand, but also system optimization for low light level or bad seeing conditions thanks to the versatility of the P-WFS. We describe the optical design, the mounting and alignment procedure and our loop control concept. Closed loop results are described, showing that while there are still many issues to fix before the sky version, the system behaves as expected.

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