Makine Mühendisliği Bölümü

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Citation - Scopus: 1
A Droplet Based Multi-Drug Screening System Controlled With Electrostatic Microvalves
(Chemical and Biological Microsystems Society, 2012) Yildirim, E.; Yıldırım, Ender; Özgür, E.; Külah, H.; 31835; Makine Mühendisliği
This paper presents a droplet-based drug effect analysis system utilizing electrostatically-actuated normallyclosed microvalves to screen the effect of multiple drugs on a single type of cell. Proposed system minimizes the need for off-chip equipment by utilizing parylene based electrostatic microvalves. Prototypes of the system were fabricated and tested using colored DI water and 3 μm diameter micro beads, emulating drugs and cells respectively. During the tests, micro beads could be successfully entrapped in 137 pl droplets. Tests carried out with yeast cells also yielded successful encapsulation of the cells. It was shown that, switching between the drugs could be achieved by applying 200 V dc to operate the microvalves.
Citation - WoS: 12
Citation - Scopus: 13
A Reconfigurable Microfluidic Transmitarray Unit Cell
(Ieee, 2013) Erdil, Emre; Yıldırım, Ender; Topalli, Kagan; Zorlu, Ozge; Toral, Taylan; Yildirim, Ender; Kulah, Haluk; Civi, Ozlem Aydin; 31835); Makine Mühendisliği
This paper presents a novel microfluidics based approach to develop a reconfigurable circularly polarized transmitarray unit cell. The unit cell comprises double layer nested split ring slots formed as microfluidic channels that can be filled by fluids. Split regions in the slots are realized by injecting liquid metal into the channels. Beam steering is obtained by implementing rotational phase shifting via manipulating the liquid metal in the slots. X-band unit cell prototypes are fabricated on glass substrate carrying a patterned metal film, and the slot channels are formed by Polydimethylsiloxane (PDMS) using soft lithography techniques.
Citation - Scopus: 1
A Simple Way for Estimating Mechanical Properties From Stress-Strain Diagram Using Matlab and Mathematica
(Institute of Electrical and Electronics Engineers Inc., 2019) Yılmaz, Emre; Yilmaz, E.; Yavuz, S.; Yavuz, Samet; 237938; Malzeme Bilimi ve Mühendisliği; Makine Mühendisliği
In this paper, mechanical properties of materials, e.g. ultimate tensile strength, yield stress, elastic modulus, ductility, resilience, toughness, etc., are calculated using MATLAB and Mathematica programming language and stress-strain data of any alloy. © 2019 IEEE.
Citation - Scopus: 1
An Electrostatically Actuated Parylene Microvalve for Lab-On-A-Chip Applications
(2011) Yildirim, E.; Yıldırım, Ender; Kulah, H.; Arikan, M.A.S.; 31835; Makine Mühendisliği
This paper presents a novel electrostatic microvalve to control in-plane flow on parylene based lab-on-a-chip-devices. Normally-closed design of the microvalve insulates the working fluid from the electric field, while providing low leakage up to 40 kPa inlet pressure. Prototypes are fabricated and tested for pull-in and flow characterization. Pull-in voltage is measured to be 150 V independent of the working fluid. No leakage is detected up to 20 kPa inlet pressure. © 2011 IEEE.
Citation - WoS: 1
Citation - Scopus: 2
C-3 : configurable CAN FD controller: architecture, design and hardware implementation
(Ieee, 2017) Afsin, Mehmet Ertug; Schmidt, Klaus Werner; Schmidt, Ece Guran
CAN FD (Controller Area Network with Flexible Data Rate) is a new standard which provides a fast data rate while preserving the compatibility with CAN. In this paper, we propose the C-3 (Configurable CAN FD Controller) IP core architecture, which is compatible with the non-ISO CAN FD standard. C-3 supports up to 96 transmit and receive buffers. The transmit buffers are organized as mailboxes with CAN ID prioritization in frame transmission. A separate filter mask that can be configured by the user exists for each receive buffer. Different from existing CAN/CAN FD controllers, the numbers and sizes of transmit and receive buffers of C-3 can be configured at run time. To this end, C-3 enables the best use of a single controller hardware for different applications and enables improving the real-time communication performance. C-3 communicates with the host device over SPI without any specific interface requirements using the protocol that is developed in the scope of this paper. C-3 is implemented on an FPGA Evaluation Board and its functionality is verified at a data rate of 2 Mbps.
Citation - WoS: 0
Citation - Scopus: 0
Clean Energy Generation in Residential Green Buildings- CH2
(inst Engineering Tech-iet, 2019) Yapici, Ekin Ozgirgin; Ayli, Ece
Due to the recent investigations, buildings consume a considerable amount of the electricity, drinking water, global final energy use and as a result are responsible for one third of the global carbon emissions. Therefore, building sector has a key role to reach global energy targets. In this sight, this study draws attention to the sustainable energy performances of green buildings (GBs) and aims towards the GBs concept which includes renewable sources in the construction and lifetime utilization. The remainder of the chapter is subjected as follows: Section 2.1 gives a brief information about residential GBs, and in Section 2.2, certification systems for sustainability ratings of residential GBs are given. This is followed by case studies related to the certification systems in Section 2.3 part. In Section 2.4, GBs incentives are summarized. Section 2.5 provides information about energy demand modelling for residential GBs, and in Section 2.6, clean energy generation systems in residential GBs are described in detail. Finally, outlook for the works that is performed up to now and the outlook for the future is given.
Citation - Scopus: 0
Comparison of Different Turbulent Models in Turbulent-Forced Convective Flow and Heat Transfer Inside Rectangular Cross-Sectioned Duct Heating At the Bottom Wall
(Springer International Publishing, 2014) Arslan, K.; Onur, Nevzat; Onur, N.; 53858; Makine Mühendisliği
In this study, steady-state turbulent-forced flow and heat transfer in a horizontal smooth rectangular cross-sectioned duct was numerically investigated. The study was carried out in the turbulent flow region where Reynolds number ranges from 1 × 104 to 5 × 104. The flow was developing both hydrodynamically and thermally. The bottom surface of the duct was assumed to be under constant surface temperature. A commercial CFD program Ansys Fluent 12.1 with different turbulent models was used to carry out the numerical study. Different turbulence models (k–ε Standard, k–ε Realizable, k–ε RNG, k–ω Standard and k–ω SST) were used. Based on the present numerical solutions, new engineering correlations were presented for the heat transfer and friction coefficients. The numerical results for different turbulence models were compared with each other and the experimental data available in the literature. It was observed that k–ε turbulence models represented the turbulent flow condition very well for the present study. © Springer International Publishing Switzerland 2014.
Citation - Scopus: 0
Droplet based cell screening system integrated with CMOS image sensor and android-based application
(Chemical and Biological Microsystems Society, 2020) Özkan, M.D.; Aslan, M.K.; Atik, A.C.; Özgür, E.; Yıldırım, E.; Külah, H.
This paper presents a droplet based single cell screening concept, where the cells encapsulated in microdroplets are monitored by integrating a commercial CMOS image sensor to the microfluidic chip. The images acquired through the image sensor are streamed and processed via an Android-based application on smartphone. This integrated system offers microscope-free screening of cells within the droplets based on their shapes. © 17CBMS-0001.
Citation - Scopus: 3
Electrochemical discharge machining: trends and development
(Elsevier, 2021) Perveen, A.; Akar, Samet; Akar, S.; 315516; Makine Mühendisliği
The fabrication of microscale products revolutionizes the way manufacturing industries work today and has become the demand of current era due to their applications in various fields like microfluidics, biomedical testing systems, and microelectromechanical systems. Current research interest of manufacturing industries has shifted toward micromanufacturing process development. Electrochemical discharge machining (ECDM) is one of such recently developed process well known for its capability to machine both conductive as well as nonconductive materials. This process evolved from combination of electrodischarge machining and electrochemical machining. This hybrid machining process becomes an attractive technology due to its process simplicity and application in fabrication of microscale features and three-dimensional structures. This chapter will be focusing on the state-of-the-art review of the ECDM processes and its recent development. Various form of this process such as ECDM turning, ECMD-milling, and ECDM grinding will be presented in this chapter. Based on the research found in the literature, limitation associated with ECDM process will be demonstrated, and future research trend for overcoming these drawbacks will be narrated. © 2021 Elsevier Inc. All rights reserved.
Citation - WoS: 0
Finite Element Method Application For Nonlinear Mechanical Response Of Three-Dimensonal Beams Using Mathematica
(Gazi Univ, 2019) Tanriover, Hakan; 153029
Mechanical behavior of beams under large rotations and displacements was investigated. Using co-rotational approach given by Crisfield, three dimensional beam finite elements was modeled in Mathematica environment. The symbolic process of Mathematica provides keeping the parameters in the model as variables and beams having different geometries can be modelled easily. The yielding non-linear equation system was solved by utilizing Newton-Raphson technique. Dynamic balance equations and numerical time integration method were introduced, the solution process was left as a future work, however. Comparisons with the results of ANSYS and those of the works from the literature are accomplished.
Citation - Scopus: 1
Finite element modeling of mechanical micromachining
(CRC Press, 2017) Oliaei, S.N.B.; Demiral, Murat; Demiral, M.; Makine Mühendisliği
The knowledge about all these phenomena is necessary to fabricate microparts, satisfying required dimensional and geometrical tolerances and surface quality requirements. Therefore, developing predictive techniques to improve the quality of microparts has emerged as an important research area. Several approaches have been used to predict outputs of microcutting operations including analytical modeling, numerical techniques, molecular dynamics simulation, and experimental studies. As experimental studies are costly and time consuming and as they are only valid for the conditions and range of machining parameters used in the experiments, numerical methods are used as an alternative method to predict machining process outputs. © 2018 by Taylor & Francis Group, LLC.
Citation - WoS: 0
Citation - Scopus: 0
Fluorescent on-chip imager by using a tunable absorption filter
(Ieee, 2017) Arpali, Caglar; Yıldırım, Ender; Yildirim, Ender; Arpali, Serap Altay; 20809; 31835; 51304; Makine Mühendisliği
Kesici Takım Geometrisinin Ti-6Al-4V’nin İşlenmesi Sırasında Oluşan Tırtıklı Talaş Üzerindeki Etkisinin Sonlu Elemanlar Yöntemi ile Araştırılması
(2020) Olıaei, Samad Nadimi Bavil; Yılmaz, Okan Deniz
Ti-6Al-4V titanyum alaşımının işlenmesi sırasında tırtıklı talaş (serrated chip) oluşumunun modellenmesi oldukçazordur ve takım ömrünü, işlenmiş parçanın doğruluğunu ve yüzey kalitesini etkilediği için hayati öneme sahiptir.Kesici uç geometrisinin tırtıklı talaş oluşumu üzerindeki etkisi daha ileri araştırmalar gerektirirken, termalyumuşama, deformasyon yumuşaması ve hasara dayanan modeller olmak üzere bu sorunu çözmek için çeşitlimalzeme modelleri geliştirilmiştir. Bu çalışmada, teğet hiperbolik (TANH) fonksiyon kullanarak deformasyonyumuşama etkisini dikkate alan modifiye edilmiş bir Johnson-Cook temel malzeme modeli ele alınmıştır. Farklıgeometrilere (talaş açısı, boşluk açısı ve kenar yarıçapı) sahip olan kesici takımların tırtıklı talaş oluşumu üzerindeetkileri modellenmiş ve analiz edilmiştir. Kesme kuvveti, talaş morfolojisi ve tırtıklı talaşın derecesi talaşlı imalatverisi olarak kullanılmıştır
Citation - Scopus: 4
Microchannels for microfluidic systems
(Elsevier, 2020) Nasseri, B.; Akar, S.; Naseri, E.; 315516
Microfluidic systems (which are also known as microchannel devices) are an important and versatile practical apparatus applicable in different areas of science and technology. The appropriate design of microfluidic system demands the accurate calculation of the parameters of the microfluidic device. The channels used in microfluidic systems are critical compartments of the device, which affect the efficiency of the system. The purpose of this chapter is to survey the microchannels and their characteristics in microfluidic systems. After a detailed discussion of microchannels, their applications for non-living phantoms for cardiovascular, neuroscience and respiratory studies will be discussed. In the biomedical applications of microchannels the areas such as cell studies e.g. cytoskeleton behavior, cell-to-cell interaction detecting of cell derived moieties are important. Also cellular level tissue engineering, such as cell vaso-occlusion in tissue biomimicking is described. © 2021 Elsevier Inc. All rights reserved.
Citation - Scopus: 0
Neck protection in autonomous car crashes
(Kauno Technologijos Universitetas, 2020) Yavuz, S.; Himmetoglu, S.
Autonomous cars which are expected to be on the market in the upcoming years, present new challenges to restraint system design since unconventional seating plans can put the occupants at more risk. For instance, an occupant sitting on a rear facing seat can experience higher risk of whiplash in a frontal impact considering the fact that statistically frontal impacts do happen at higher severities than rear impacts as seen in the crash test conditions of US NCAP. In this study, an improvement to car seat design is presented in which the seatback is automatically rotated into a more upright position prior to impact in order to increase the energy absorbing potential of the seatback. The study involves computer simulation of a seat-occupant system to demonstrate the benefits of the proposed system. © 2020 Kaunas University of Technology. All rights reserved.
Citation - Scopus: 0
Phaseguide assisted liquid lamination for magnetic bead-based assays
(Chemical and Biological Microsystems Society, 2013) Phurimsak, C.; Yıldırım, Ender; Yildirim, E.; Trietsch, S.J.; Hankemeier, T.; Tarn, M.D.; Pamme, N.; Vulto, P.; Makine Mühendisliği
We demonstrate a simple, pump-free platform for performing rapid magnetic bead-based processes via their transfer through sequentially laminated liquid streams, made possible by the use of phaseguide technology. We have applied this strategy to two on-chip assays: (i) a streptavidin-biotin binding assay, and (ii) a sandwich immunoassay for the detection of C-reactive protein (CRP). Here, functionalized magnetic beads were pulled through alternating lanes of reagents and buffer solution, allowing multiple binding and washing processes to be reduced into a single step, significantly shortening procedural times compared to conventional multi-step bead-based assays.
Prediction of Nusselt Number of Rectangular Fins Using Artificial Neural Network Model
(2019) Aylı, Ece; 265836
Pasif ısı transferi iyileştirme metodlarında ısı transferi kat sayısı ve Nusselt sayısını maximize ederken, basınç düşümünü minimize eden yaklaşımı tespit edebilmek için bir çok parametrenin optimizasyonunun yapılması gerekmektedir. Bu sebepten ötürü, deneysel ve sayısal çalışmalara bağlı olarak ampirik korelasyonlar elde edilmektedir. Bu çalışmada dikdörtgensel finlerin ısı transferi davranışı deneysel ve yapay sinir ağları metodları ile ortaya konmuştur. Yapay sinir ağları metodolojisi ile elde edilen sonuçlar korelasyon ile kıyaslanmıştır. Ayrıca, tanımlanan problem için yapay sinir ağı uygulamasında farklı eğitim algoritmalarının ve katman sayısının sonuçlar üzerindeki etkisi araştırılmıştır. Elde edilen sonuçlara göre YSA yöntemi, korelasyon yönteminden daha hızlı ve daha doğru sonuç vermektedir. Diğer yandan YSA yaklaşımının doğruluğunun arttırılması için uygun eğitim algoritmasının seçimi, uygun katman sayısının tespiti yani uygun mimarinin elde edilmesi önem arz etmektedir. Tanımlanan bu problem için, 10-5-1 ağına sahip Bayesian Regularization algoritması %7.6 ortalama yüzde hata ve 0.029 RMSE ile iyi senaryo olarak belirlenmiştir. Maximum ortalama hata %56.3 ile Levenberg- Marquardt algoritmasında 10-12-1 ağı ile elde edilmiştir.
Review of Enhancement of Heat Transfer From Rectangular Fin Arrays
(2018) Aylı, Ece; İnce, Ender; 265836
Birçok mühendislik probleminde ısı transferi oranları önemli bir etkiye sahiptir. Otomotiv, havalandırma, elektronik soğutma, hava aracı gibi birçok endüstriyel uygulama alanında ısı artımı, ekipmanlarda fazla ısınmaya neden olarak sistem hatalarına, kısa makine ömrüne, güvenilirliğin düşmesine ve bakım ihtiyacının artmasına neden olmaktadır. Bu tip problemlerin önüne geçilmesinde pasif soğutma teknikleri sıklıkla kullanılmaktadır. Bu derleme makalesinde yüksek verim ve düşük maliyet ile ısı transferi iyileştirmesi sağlayan pasif soğutma tekniklerinden olan dikdörtgen kanatçıklar araştırılmıştır. Ayrıca dikdörtgen kanatçıkların eğimli, delikli, aralıklı, hizalı ve kaydırılmış olarak kullanılmasının ısı transferine olan etkilerinin araştırıldığı birçok makale de özetlenmiştir. Kanatçıklı yapılar ile ısı transferini arttırmak için tasarımcılar, kanatçık uzunluğu, kanatçık şekli, kanatçık genişliği, kanatçık sayısı, kanatçıklar arası mesafeler gibi birçok parametreyi optimize etmek mecburiyetindedir. Bu optimizasyon sürecinde deneyim sahibi olmayan bir tasarımcı, ısı transferini arttırmak yerine, tasarladığı kanatçıklı yapı ile gelen havanın ısınan hava ile karışmasını engelleyip ısı transferi üzerinde tam tersi etki yaratabilmektedir. Bu derleme makalesi ıs transferiini dikdörtgen kanatçık kullanarak maksimize etmek isteyen tasarımcılar için bir rehber niteliğindedir ve literatürde bu konu ile yapılmış geniş bir spektrumu taramaktadır.
Citation - Scopus: 4
Small-scale mechanical properties of additively manufactured Ti-6Al-4V
(The University of Texas at Austin, 2020) Haghshenas, M.; Totuk, O.; Masoomi, M.; Thompson, S.M.; Shamsaei, N.; 284521
This article aims at studying microstructure and nano/micro-scale mechanical responses of Ti-6Al4V fabricated using a Laser-based Powder Bed Fusion (L-PBF) method. To this end, an instrumented depth-sensing nanoindentation system has been used to assess hardness, Young's modulus, strain rate sensitivity and rate dependent plastic deformation of the alloy at different build Orientations (in the Z-plane and X-plane) at ambient temperature. Indentation tests were conducted at constant proportional loading rate of 15 mN/s in a depth-controlled (hind=2000 nm) testing regime. The Microstructure characterizations were performed using optical and scanning electron microscopy to assess the correlations to the mechanical properties achieved by the nanoindentation testing to better establish structure-property relationships for L-PBF Ti-6Al-4V. It is expected that the fine microstructure, developed by fast solidification during the L-PBF process, to directly contribute to the nanoindentation measurements at different strain rates. Copyright © SFF 2017.All rights reserved.
Strengthening Effect Of Flooding In 3d Printed Porous Soft Robotics Scaffolds
(2021) Selvi, Özgün; Totuk, Onat Halis; Arslan, Ozan; Arslan, Ozan; Selvi, Özgün; Mıstıkoglu, Selçuk; Totuk, Onat; Makine Mühendisliği; Mekatronik Mühendisliği
This study aims to design and 3D print porous elements for soft robotic applications and test the stiffness changes when the cavities are filled with liquids. When an elastic element has porous scaffolds, the stiffness can be controlled by filling the cavities with a liquid. A gyroid structure is selected for the design and evaluation of the characteristics of elements. The stiffness of the element in both non-filled and liquid-filled modes is analyzed using FEM simulation Software in two modes where simple support with central loading and compressive uniform loading. A porous test structure is created and tested in these modes for observation of the stiffness change. Employing an FDM printer in this project enabled us to make our thoughts to reality. The results show that liquid-filling can be used as a stiffening method for porous scaffolds in soft robotic applications.

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