Mühendislik Bilimleri Bölümü Koleksiyonu

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

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Assessment of biocompatibility of novel TiTaHf-based high entropy alloys for utility in orthopedic implants
(ELSEVIER SCIENCE SAPO BOX 564, 1001 LAUSANNE, SWITZERLAND, 2021) Gurel, S.; Nazarahari, A.; Canadinc, D.; Cabuk, H.; Bal, B.; AGÜ, Mühendislik Fakültesi, Makine Mühendisliği Bölümü; Bal, B.
This paper presents the findings of experimentally observed corrosion response of novel TiTaHf-based high entropy alloys (HEAs) in fetal bovine serum (FBS) to evaluate their biocompatibility in presence of proteins and potential to be used as implant materials. Particularly, TiTaHfNb, TiTaHfNbZr and TiTaHfMoZr HEAs were subjected to static immersion experiments in FBS media, and both the HEA samples and the immersion fluids underwent thorough characterization. The findings presented herein show that Zr and Mo addition to the TiTaHf solid solution increased the total ion release from the resulting HEAs in FBS, while the TiTaHfNb HEA became prominent in terms of biocompatibility owing to the reduced ion release in FBS. Moreover, hydroxy apatite (HA) formation was evident on the surfaces of all three HEAs upon immersion in FBS, indicating the potential of the three TiTaHf-based HEAs to form desired binding with the human bone. Considering the fact that passive oxide layer formation facilitating lower susceptibility to corrosion in long-term applications was also observed in the studied HEAs, further elaboration on their mechanical and biological responses is warranted for the sake of a comprehensive assessment regarding their utility as orthopedic implant materials.
A fractional-order mathematical model based on vaccinated and infected compartments of SARS-CoV-2 with a real case study during the last stages of the epidemiological event
(ELSEVIER, 2023) Bilgil, Halis; Yousef, Ali; Erciyes, Ayhan; Erdinc, Ummugulsum; Ozturk, Zafer; AGÜ, Mühendislik Fakültesi, Mühendislik Bilimleri Bölümü; Yousef, Ali
In 2020 the world faced with a pandemic spread that affected almost everything of humans’ social and health life. Regulations to decrease the epidemiological spread and studies to produce the vaccine of SARS-CoV-2 were on one side a hope to return back to the regular life, but on the other side there were also notable criticism about the vaccines itself. In this study, we established a fractional order differential equations system incorporating the vaccinated and re-infected compartments to a SIR frame to consider the expanded and detailed form as an SVIIvR model. We considered in the model some essential parameters, such as the protection rate of the vaccines, the vaccination rate, and the vaccine’s lost efficacy after a certain period. We obtained the local stability of the disease-free and co-existing equilibrium points under specific conditions using the Routh–Hurwitz Criterion and the global stability in using a suitable Lyapunov function. For the numerical solutions we applied the Euler’s method. The data for the simulations were taken from the World Health Organization (WHO) to illustrate numerically some scenarios that happened
Investigations of Electrical Resistivity and Thermal Conductivity Dependences on Growth Rate in the Al-Cu-Ti Eutectic Alloy
(SPRINGER/PLENUM PUBLISHERS233 SPRING ST, NEW YORK, NY 10013, 2021) Marasli, Necmettin; Bayram, Umit; AGÜ, Mühendislik Fakültesi, Mühendislik Bilimleri Bölümü; Bayram, Umit
Directional solidification of Al-Cu-Ti (Al-33wt%Cu-0.1wt%Ti) eutectic alloy was done with a growth rate range (V = 8.58 to 2038.65 mu m.s(-1)) at a temperature gradient of 6.45 K.mm(-1) using Bridgman-type directional solidification furnace. The measurements of thermal conductivity (K) and electrical resistivity (rho) for the Al-Cu-Ti alloy solidified with the different values of V were made by the longitudinal heat flow method (LHFM) and DC four-point probe technique (FPPT). While the highest values of K and rho were determined to be 236.04 W.K-1.m(-1) and 5.91 x 10(-8) omega m, respectively, at 8.58 mu m.s(-1), the lowest values of K and rho were obtained to be 199.82 W.K-1.m(-1) and 12.11 x 10(-8) omega m, respectively, at 2038.65 mu m.s(-1). The K and rho dependences on V were obtained to be K=259.96xV(-0.032) and rho=4.47x10(-8)V(0.13) from linear regression analysis. The fusion enthalpy ( increment H) and specific heat difference between solid and liquid ( increment C-P) for the Al-Cu-Ti were also determined to be 222.69 J.g(-1) and 0.266 Jg(-1).K-1, respectively, by means of differential scanning calorimetry (DSC).
Near- and Far-Field Characterization of Planar mm-Wave Antenna Arrays with Waveguide-to-Microstrip Transition
(SPRINGERONE NEW YORK PLAZA, SUITE 4600 , NEW YORK, NY 10004, UNITED STATES, 2016) Salhi, Mohammed Adnan; Kazemipour, Alireza; Gentille, Gennaro; Spirito, Marco; Kleine-Ostmann, Thomas; Schrader, Thorsten; AGÜ, Mühendislik Fakültesi, Mühendislik Bilimleri Bölümü; Kazemipour, Alireza
We present the design and characterization of planar mm-wave patch antenna arrays with waveguide-to-microstrip transition using both near- and far-field methods. The arrays were designed for metrological assessment of error sources in antenna measurement. One antenna was designed for the automotive radar frequency range at 77 GHz, while another was designed for the frequency of 94 GHz, which is used, e.g., for imaging radar applications. In addition to the antennas, a simple transition from rectangular waveguide WR-10 to planar microstrip line on Rogers 3003 (TM) substrate has been designed based on probe coupling. For determination of the far-field radiation pattern of the antennas, we compare results from two different measurement methods to simulations. Both a far-field antenna measurement system and a planar near-field scanner with near-to-far-field transformation were used to determine the antenna diagrams. The fabricated antennas achieve a good matching and a good agreement between measured and simulated antenna diagrams. The results also show that the far-field scanner achieves more accurate measurement results with regard to simulations than the near-field scanner. The far-field antenna scanning system is built for metrological assessment and antenna calibration. The antennas are the first which were designed to be tested with the measurement system.
NeRNA: A negative data generation framework for machine learning applications of noncoding RNAs
(PERGAMON-ELSEVIER SCIENCE, 2023) Orhan, Mehmet Emin; Demirci, Yilmaz Mehmet; Sacar Demirci, Muserref Duygu; 0000-0002-1757-1374; 0000-0003-3802-4211; 0000-0003-2012-0598; AGÜ, Yaşam ve Doğa Bilimleri Fakültesi, Biyomühendislik Bölümü; Orhan, Mehmet Emin; Demirci, Yilmaz Mehmet; Sacar Demirci, Muserref Duygu
Many supervised machine learning based noncoding RNA (ncRNA) analysis methods have been developed to classify and identify novel sequences. During such analysis, the positive learning datasets usually consist of known examples of ncRNAs and some of them might even have weak or strong experimental validation. On the contrary, there are neither databases listing the confirmed negative sequences for a specific ncRNA class nor standardized methodologies developed to generate high quality negative examples. To overcome this challenge, a novel negative data generation method, NeRNA (negative RNA), is developed in this work. NeRNA uses known examples of given ncRNA sequences and their calculated structures for octal representation to create negative sequences in a manner similar to frameshift mutations but without deletion or insertion. NeRNA is tested individually with four different ncRNA datasets including microRNA (miRNA), transfer RNA (tRNA), long noncoding RNA (lncRNA), and circular RNA (circRNA). Furthermore, a species-specific case analysis is performed to demonstrate and compare the performance of NeRNA for miRNA prediction. The results of 1000 fold cross-validation on Decision Tree, Naïve Bayes and Random Forest classifiers, and deep learning algorithms such as Multilayer Perceptron, Convolutional Neural Network, and Simple feedforward Neural Networks indicate that models obtained by using NeRNA generated datasets, achieves substantially high prediction performance. NeRNA is released as an easy-to-use, updatable and modifiable KNIME workflow that can be downloaded with example datasets and required extensions. In particular, NeRNA is designed to be a powerful tool for RNA sequence data analysis.
On rings with one middle class of injectivity domains
(UNIV OSIJEK, DEPT MATHEMATICSUNIV OSIJEK, DEPT MATHEMATICS, TRG LJUDEVITA GAJA 6, OSIJEK HR-31000, CROATIA, 2022) Demirci, Yilmaz Mehmet; Alizade, Rafail; Turkmen, Burcu Nisanci; Turkmen, Ergul; 0000-0003-3802-4211; 0000-0003-4444-9136; AGÜ, Mühendislik Fakültesi, Mühendislik Bilimleri Bölümü; Demirci, Yilmaz Mehmet
A module M is said to be modest if the injectivity domain of M is the class of all crumbling modules. In this paper, we investigate the basic properties of modest modules. We provide characterizations of some classes of rings using modest modules. In particular, we show that a ring having the class of crumbling modules as the only right middle class of injectivity domains is either a right V-ring or right Noetherian; and a commutative ring with this property is regular. We also give criteria for a ring having the class of crumbling modules as the only right middle class of injectivity domains.
Organic semiconductor based surface-enhanced Raman spectroscopy platforms
(AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA, 2018) Demirel, Gokhan; Usta, Hakan; Facchetti, Antonio; 0000-0002-9778-917X; 0000-0002-0618-1979; AGÜ, Mühendislik Fakültesi, Mühendislik Bilimleri Bölümü
Conference Conference: 256th National Meeting and Exposition of the American-Chemical-Society (ACS) - Nanoscience, Nanotechnology and Beyond Location: Boston, MA Date: AUG 19-23, 2018 Sponsor(s):Amer Chem Soc
Performance analysis of photonic lantern based coherent receivers
(NATL INST OPTOELECTRONICS, 1 ATOMISTILOR ST, PO BOX MG-5, BUCHAREST-MAGURELE 76900, ROMANIA, 2018) Oran, A.; Ozdur, I.; 0000-0001-6452-0804; AGÜ, Mühendislik Fakültesi, Mühendislik Bilimleri Bölümü
In this paper, we present the simulation results for bit-error-rate improvements of photonic lantern based coherent LIDAR systems. Our results show that using a 19-port photonic lantern, the bit-error-rate can be improved to 0.06 from 0.30 for a range of 100 meters, corresponds to a detection rate improvement from 70% to 94%.
Preface of Mini Symposia of 82-Statistical Methods and Applications in Engineering
(American Institute of Physics Inc., 2018) Greenacre, Zerrin Aşan; Atay, Mehmet Tarık; Gazeloǧlu, Cengiz; 0000-0002-8222-3384; AGÜ, Mühendislik Fakültesi, Mühendislik Bilimleri Bölümü; Atay, Mehmet Tarık; Gazeloǧlu, Cengiz
Preface of Mini Symposia of 82-Statistical Methods and Applications in Engineering
Preface of the Symposium on: "advances in Analytical, Analytical Approximate, Numerical and Asymptotic Analysis of Sturm-Liouville Problems with the Applications in Engineering"
(American Institute of Physics Inc., 2017) Atay, Mehmet Tarik; Erdogan, Hakan; AGÜ, Mühendislik Fakültesi, Mühendislik Bilimleri Bölümü; Atay, Mehmet Tarik
Preface of the Symposium on: "advances in Analytical, Analytical Approximate, Numerical and Asymptotic Analysis of Sturm-Liouville Problems with the Applications in Engineering"
Rings with modules having a restricted injectivity domain
(SPRINGER INTERNATIONAL PUBLISHING AG, GEWERBESTRASSE 11, CHAM, CH-6330, SWITZERLAND, 2019) Demirci, Yilmaz Mehmet; Turkmen, Burcu Nisanci; Turkmen, Ergul; 0000-0003-3802-4211; AGÜ, Mühendislik Fakültesi, Mühendislik Bilimleri Bölümü
We introduce modules whose injectivity domains are contained in the class of modules with zero radical and call them working-class. This notion gives a generalization of poor modules that have minimal injectivity domain. Semisimple working-class modules always exist for arbitrary rings whereas their predecessors do not. We investigate the rings over which every module is either injective or working-class. Right weakly V-rings are examples of these rings. Moreover, we study the existence of working-class simple modules and show that if there is a projective working-class simple right module, then the ring is a right GV-ring.
RINGS WITH VARIATIONS OF FLAT COVERS
(HONAM MATHEMATICAL SOC, DEPT MATHEMATICS, COLL NATURAL SCIENCE, CHOSUN UNIV, 309, PILMUN-DAERO, DONG-GU, GWANGJU, 501-759, SOUTH KOREA, 2019) Demirci, Yilmaz Mehmet; Turkmen, Ergul; 0000-0003-3802-4211; AGÜ, Mühendislik Fakültesi, Mühendislik Bilimleri Bölümü
We introduce flat e-covers of modules and define e-perfect rings as a generalization of perfect rings. We prove that a ring is right perfect if and only if it is semilocal and right e-perfect which generalizes a result due to N. Ding and J. Chen. Moreover, in the light of the fact that a ring R is right perfect if and only if flat covers of any R-module are projective covers, we study on the rings over which flat covers of modules are (generalized) locally projective covers, and obtain some characterizations of (semi) perfect, A-perfect and B-perfect rings.

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