Mühendislik Bilimleri Bölümü Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/36

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Analysis of the motion of a rigid rod on a circular surface using interpolated variational iteration method
(YILDIZ TECHNICAL UNIV, 2022) Coskun, Safa Bozkurt; Senturk, Erman; Atay, Mehmet Tarik; AGÜ, Mühendislik Fakültesi, Mühendislik Bilimleri Bölümü; Atay, Mehmet Tarik
In this paper, interpolated variational iteration method (IVIM) is applied to investigate the vibration period and steady-state response for the motion of rigid rod rocking back and forth on a circular surface without slipping. The problem can be considered as a strongly nonlinear oscillator. In this solution procedure, analytical variational iteration technique is utilized by evaluating the integrals numerically. The approximate analytical results produced by the presented method are compared with the other existing solutions available in the literature. The advantage of using numerical evaluation of integrals, the method becomes fast convergent and a highly accurate solution can be obtained within seconds. The authors believe that the presented technique has potentially wide application in the other nonlinear oscillation problems.
Deformation classification of quartic surfaces with simple singularities
(EUROPEAN MATHEMATICAL SOC-EMS, 2024) Aktaş, Çisem Güneş; 0000-0002-6425-9156; AGÜ, Mühendislik Fakültesi, Mühendislik Bilimleri Bölümü; Aktaş, Çisem Güneş
We give a complete equisingular deformation classification of simple spatial quartic surfaces which are in fact K3-surfaces.
DETERMINATION OF 1/V-T (P, CONSTANT) DIAGRAMS OF HYDROGEN GASES BY GRAPH-ANALYTICAL METHODS
(YILDIZ TECHNICAL UNIV, YILDIZ CAMPUS, BESIKTAS, ISTANBUL, 34349, TURKEY, 2017) Ibrahimoglu, Beycan; Kanbes Dindar, Cigdem; Erol, Hazal; Karasari, Salih; AGÜ, Mühendislik Fakültesi, Mühendislik Bilimleri Bölümü;
Graph-analytical methods provide more accurate results in the analysis of V-T (P=constant) and 1/V-T (P=constant) diagrams of gases. In this study, as a continuation of [1, 2]*, the behavior of hydrogen gas was examined by using graph-analytical method under consideration of volume and density parameters at high pressure and temperature. In this paper, graph-analytical method was applied to draw and examine V-T (P=constant) and 1/V-P (T=constant) diagrams which were based on experimental data of hydrogen and other gases (Hydrogen, carbon dioxide, oxygen, argon, helium, neon, xenon and other gases) at high pressure and temperature. The results indicate that the behavior of hydrogen gas is different from the other gases.
Geography of irreducible plane sextics
(Oxford University Press, 2015) Akyol, Ayşegül; Degtyarev, Alex; AGÜ, Mühendislik Fakültesi, Mühendislik Bilimleri Bölümü; Akyol, Ayşegül
We complete the equisingular deformation classification of irreducible singular plane sextic curves. As a by-product, we also compute the fundamental groups of the complement of all but a few maximizing sextics.
Glucose-dependent anaplerosis in cancer cells is required for cellular redox balance in the absence of glutamine
(NATURE PUBLISHING GROUP, MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND, 2016) Cetinbas, Naniye Malli; Sudderth, Jessica; Harris, Robert C.; Cebeci, Aysun; Negri, Gian L.; Yilmaz, Oemer H.; DeBerardinis, Ralph J.; Sorensen, Poul H.; AGÜ, Mühendislik Fakültesi, Mühendislik Bilimleri Bölümü;
Cancer cells have altered metabolism compared to normal cells, including dependence on glutamine (GLN) for survival, known as GLN addiction. However, some cancer cell lines do not require GLN for survival and the basis for this discrepancy is not well understood. GLN is a precursor for antioxidants such as glutathione (GSH) and NADPH, and GLN deprivation is therefore predicted to deplete antioxidants and increase reactive oxygen species (ROS). Using diverse human cancer cell lines we show that this occurs only in cells that rely on GLN for survival. Thus, the preference for GLN as a dominant antioxidant source defines GLN addiction. We show that despite increased glucose uptake, GLN addicted cells do not metabolize glucose via the TCA cycle when GLN is depleted, as revealed by C-13-glucose labeling. In contrast, GLN independent cells can compensate by diverting glucose-derived pyruvate into the TCA cycle. GLN addicted cells exhibit reduced PDH activity, increased PDK1 expression, and PDK inhibition partially rescues GLN starvation-induced ROS and cell death. Finally, we show that combining GLN starvation with pro-oxidants selectively kills GLN addicted cells. These data highlight a major role for GLN in maintaining redox balance in cancer cells that lack glucose-dependent anaplerosis.
ILGIN LİNYİT İŞLETMELERİ GÖLETLERİNDE ASİT MADEN DRENAJI VE REHABİLİTASYONU
(Niğde Ömer Halisdemir Üniversitesi, 2016) Delibalta,Mahmut Suat; Uzal, Niğmet; 0000-0002-0912-3459; AGÜ, Mühendislik Fakültesi, Mühendislik Bilimleri Bölümü; Uzal, Niğmet
Maden yataklarının aranması, üretimi ve zenginleştirilmesi süreçlerinde uygulanan işlemler; hava, toprak, sukaynaklarını, dolayısıyla çevreyi ve çevrede yaşayan canlıları etkilemektedir. Genel olarak kömür açık işletmemadenciliğinin çevre üzerindeki olumsuz etkileri, yeraltı madenciliği ve cevher hazırlama çalışmalarına oranlaçok daha fazladır.Kömür açık işletmeleri sonrası oluşan üretim çukurlarının dekapaj malzemesiyle doldurulmaması halinde,yüzey suları ve yeraltı su seviyesinin yükselmesi ile küçük veya büyük göletler oluşmaktadır. Düşük pH değeri(asidik karakteristik) ve yüksek metal konsantrasyonu (Al, Ca, Mn, Fe, Cu, Zn, Pb) içeren bu göletlerde, baskınhalde bulunabilen sülfürlü mineraller ve atık malzemeler en önemli çevresel sorunlardan birini oluşturmaktadır.Bu çalışmada, TKİ GLİ Ilgın linyit işletmeleri 5 farklı gölette su karakterizasyonu izlemeleri yapılarak;ortalama pH 6,49-7,81, bulanıklık (NTU) 0,12-63,6, sülfat içeriği 0,05-2,67 mg SO4/L, kimyasal oksijen ihtiyacı4-136 mg O2/L, elektriksel iletkenlik 285 µS/cm-4,68 mS/cm değerleri ve 1839 ppb Mn, 9777 ppb Fe ile enyüksek ağır metal içerikleri tespit edilmiştir. Saha örneklerine ilişkin analizler üç aylık periyotlarla takipedilmiştir. Belirlenen sonuçlar ilgili yasal yönetmelikler çerçevesinde değerlendirilmiştir.
A Laser-Assisted Cellular Electrophysiology Measurement System
(IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC445 HOES LANE, PISCATAWAY, NJ 08855-4141, 2021) Seymen, A. A.; Ozgur, E.; Soran-Erdem, Z.; Ortac, B.; 0000-0001-7607-9286; AGÜ, Mühendislik Fakültesi, Mühendislik Bilimleri Bölümü; Soran-, Erdem, Z.
Patch-clamp technique is the gold standard for cellular electrophysiological measurements, which is capable of measuring single ion transport events across the cell membrane. However, the measurement possesses significant complexities, and it requires a high level of expertise, while its experimental throughput is nevertheless considerably low. Here, we suggest and experimentally demonstrate a laser-assisted method for performing cellular electrophysiological measurements. Femtosecond laser pulses, coupled to an optical microscope, are used to form a sub-micrometer hole on a thin polymer membrane separating two electrodes, where a nearby cell is subsequently placed onto the hole by negative pressure. Afterwards, the cell is punctured using subsequent laser exposure, revealing the cell membrane over the hole for electrophysiological recording. This system could be used to increase the output amount of the electrophysiological measurements substantially.
Magnetic-particle based signal amplification method integrated with mobile-devices for low cost biosensing
(ELSEVIER SCIENCE BV, SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS, 2017) Mzava, Omary; Tas, Zehra; Lafci, Vahit Can; Cakar, Mehmet Akif; Ozdur, Ibrahim; Icoz, Kutay; AGÜ, Mühendislik Fakültesi, Mühendislik Bilimleri Bölümü;
We present a signal amplification method for biosensing applications using magnetic particles. In this method, mobile devices and simple spherical glass beads are used as a low-cost microscope to detect magnetic particles. Magnetic particles have two main functions; 1) conventionally capture, separate and transport target molecules 2) form magnetic dipoles under an applied external magnetic field to attract other magnetized particles. When magnetic particles accumulate and form a cluster, the corresponding pixel area in the image taken by the simple microscope is increased resulting in signal amplification. Current focus of new generation biosensor research is to increase the sensitivity levels of the devices to compete with current lab analysis tools while inherently having other advantages such as being low-cost, portable and simple. Biosensors based on micro/nano magnetic particles use various measurement techniques and amplification methods. In order to fully benefit from the advantages of micro/nano technology based systems, measurement set up must be also portable and have high sensitivity. Mobile devices and applications are taking place in medical fields and have high potential for future. In this work mobile devices are employed as measurement setups for the magnetic particle based sensing and signal amplification. The amplification method is not based on bimolecular binding thus cost efficient. After the images of the magnetic particles are taken, these images are sent to cloud computing for analysis by the mobile device. Matlab codes run on cloud servers for processing the images. Finally results are received and displayed on the mobile device. The mobile device based imaging system is able to detect 7 mu m size particles within a 1500 mu m x1500 mu m area and magnetic bead accumulation resulted in at least 5-fold signal amplification. The applied magnetic field is approximately 15 mT and the cost of the system excluding mobile device is under 20 cents. The method is promising for immunomagnetic bead assisted biosensors. (c) 2016 The Authors. Published by Elsevier Ltd.
A new approaching method for linear neutral delay differential equations by using Clique polynomials
(TUBİTAK, 2023) YÜZBAŞI, Şuayip; TAMAR, Mehmet Emin; 0000-0001-8933-8769; AGÜ, Mühendislik Fakültesi, Mühendislik Bilimleri Bölümü; TAMAR, Mehmet Emin
This article presents an efficient method for obtaining approximations for the solutions of linear neutral delay differential equations. This numerical matrix method, based on collocation points, begins by approximating y ′ (u) using a truncated series expansion of Clique polynomials. This method is constructed using some basic matrix relations, integral operations, and collocation points. Through this method, the neutral delay problem is transformed into a system of linear algebraic equations. The solution of this algebraic system determines the coefficients of the approximate solution obtained by this method. The efficiency, accuracy, and error analysis of this method are demonstrated by applying it to several numerical problems. All calculations in this method have been performed using the computer program MATLAB R2021a.
On a class of Harada rings
(DE GRUYTER POLAND SP Z O O, 2022) Türkmen Nişancı, Burcu; Demirci, Yilmaz Mehmet; 0000-0003-3802-4211; AGÜ, Mühendislik Fakültesi, Mühendislik Bilimleri Bölümü; Demirci, Yılmaz Mehmet
In this study, inspired by the definition and a previous study [F. Eryilmaz, SS -lifting modules and rings, Miskolc Math. Notes 22 (2021), no. 2, 655-662], left Harada rings are adapted to ss-Harada rings, and the important properties of these rings are provided. The characterization of a left ss-Harada ring R with R left perfect and Rad(R) included in Soc(RR) was found with the help of strongly local R-modules.
A Semi-Analytic Method for Solving Singularly Perturbed Twin-Layer Problems with a Turning Point
(Vilnius Gediminas Technical University, 2023) Cengizci, Süleyman; Kumar, Devendra; Atay, Mehmet Tarık; 39896; AGÜ, Mühendislik Fakültesi, Mühendislik Bilimleri Bölümü; Atay, Mehmet Tarık
This computational study investigates a class of singularly perturbed second-order boundary-value problems having dual (twin) boundary layers and simple turning points. It is well-known that the classical discretization methods fail to resolve sharp gradients arising in solving singularly perturbed differential equations as the perturbation (diffusion) parameter decreases, i.e., ε → 0+ . To this end, this paper proposes a semi-analytic hybrid method consisting of a numerical procedure based on finite differences and an asymptotic method called the Successive Complementary Expansion Method (SCEM) to approximate the solution of such problems. Two numerical experiments are provided to demonstrate the method’s implementation and to evaluate its computational performance. Several comparisons with the numerical results existing in the literature are also made. The numerical observations reveal that the hybrid method leads to good solution profiles and achieves this in only a few iterations.
Square root computation in finite fields
(Springer Link, 2024) Adiguzel-Goktas, Ebru; Ozdemir, Enver; AGÜ, Mühendislik Fakültesi, Bilgisayar Mühendisliği Bölümü; Adiguzel-Goktas, Ebru
In this paper, we present a review of three widely-used practical square root algorithms. We then describe a unifying framework where each of these well-known algorithms can be seen as a special case of it. The framework with singular curves offers a broad perspective to compare and further improve the existing methods in addition to offering a new avenue for square root computation algorithms in finite fields.
Tailored Synthesis of Iron Oxide Nanocrystals for Formation of Cuboid Mesocrystals
(AMER CHEMICAL SOC1155 16TH ST, NW, WASHINGTON, DC 20036, 2021) Soran-Erdem, Zeliha; Sharma, Vijay Kumar; Hernandez-Martinez, Pedro Ludwig; Demir, Hilmi Volkan; AGÜ, Mühendislik Fakültesi, Mühendislik Bilimleri Bölümü; Soran-Erdem, Zeliha
In this work, we systematically studied the shape- and size-controlled monodisperse synthesis of iron oxide nanocrystals (IONCs) for their use as building blocks in the formation of mesocrystals. For this aim, on understanding the influence of the oleic acid concentration, iron-oleate concentration, and heating rate on the synthesis of robust and reproducible IONCs with desired sizes and shapes, we synthesized highly monodisperse similar to 11 nm sized nanocubes and nanospheres. Magnetic measurements of both cubic and spherical IONCs revealed the presence of mixed paramagnetic and superparamagnetic phases in these nanocrystals. Moreover, we observed that the magnetic moments of the nanocubes are more substantial compared to their spherical counterparts. We then demonstrated a simple magnetic-field-assisted assembly of nanocubes into three-dimensional (3D) cuboid mesocrystals while nanospheres did not form any mesocrystals. These findings indicate that small cubic nanocrystals hold great promise as potential building blocks of 3D magnetic hierarchical structures with their superior magnetic properties and mesocrystal assembly capability, which may have high relevance in various fields ranging from high-density data storage to biomedical applications.
WSA-Supplements and Proper Classes
(MDPIST ALBAN-ANLAGE 66, CH-4052 BASEL, SWITZERLAND, 2022) Demirci, Yilmaz Mehmet; Turkmen, Ergul; 0000-0003-3802-4211; 0000-0002-7082-1176; AGÜ, Mühendislik Fakültesi, Mühendislik Bilimleri Bölümü; Demirci, Mehmet Yılmaz
In this paper, we introduce the concept of wsa-supplements and investigate the objects of the class of short exact sequences determined by wsa-supplement submodules, where a submodule U of a module M is called a wsa-supplement in M if there is a submodule V of M with U + V = M and U ∩ V is weakly semiartinian. We prove that a module M is weakly semiartinian if and only if every submodule of M is a wsa-supplement in M. We introduce CC-rings as a generalization of C-rings and show that a ring is a right CC-ring if and only if every singular right module has a crumbling submodule. The class of all short exact sequences determined by wsa-supplement submodules is shown to be a proper class which is both injectively and co-injectively generated. We investigate the homological objects of this proper class along with its relation to CC-rings.

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