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Öğe Investigation of the electromagnetic shielding efficiency of FeB and Fe2B: ab-initio calculations(Institute of Physics, 2024) Üşenti, Hakan; Duru, İzzet ParuğThe electromagnetic (EM) pollution that we are exposed to in our daily lives has reached levels that threaten the health of living organisms and the stable operation of sensitive systems. The most effective way to protect against this pollution is to create isolated areas framed with shielding materials that can minimize the transmission of EM radiation. The development of shielding materials with high physical endurance against external factors to meet the needs of various sectors remains a popular research topic. This process, which started with metal plates, has continued with the development of doped polymers and composite materials. In recent years, materials with 2D structures have been developed. In this study, the shielding effectiveness (SE) of FeB and Fe2B nanostructures are revealed using ab initio calculations in Perdew-Burke-ErnzerhofSol scheme. SE has been widely figuring out via optical properties which are strongly related to mechanical and electronic properties herewith magnetic phases. The ferrimagnetic FeB and Fe2B nanostructures are considered. Besides, we focus on the thickness and photon energy dependent behavior along various projections. The findings demonstrate shielding performance at levels of >20 dB. Although both materials show similar shielding performance, it is observed that Fe2B is promising when compared to FeB. This study demonstrates that FeB and Fe2B, members of the MBene family, are promising materials not only because of their superior physical and chemical properties but also because of their shielding performance.Öğe DDoS detection in electric vehicle charging stations: A deep learning perspective via CICEV2023 dataset(Elsevier B.V., 2024) Anlı, Yağız Alp; Çıplak, Zeki; Sakalıuzun, Murat; İzgü, Şeniz Zekiye; Yıldız, KazımDistributed Denial of Service (DDoS) attacks have always been an important research topic in the field of information security. Regarding specialized infrastructures such as electric vehicle charging stations, detecting and preventing such attacks becomes even more critical. In the existing literature, most studies on DDoS attack detection focus on traditional methods that analyze network metrics such as network traffic, packet rates, and number of connections. These approaches attempt to detect attacks by identifying anomalies and irregularities in the network, but can have high error rates and fail to identify advanced attacks. Conversely though, detection methods based on system metrics use deeper and more insightful parameters such as processor utilization, memory usage, disk I/O operations, and system behavior. Such metrics provide a more detailed perspective than network-based approaches, allowing for more accurate detection of attacks. However, work in this area is not yet widespread enough further research and improvement are needed. The adoption of advanced system metrics-based methods can significantly improve the effectiveness of DDoS defense strategies, especially in next-generation and specialized infrastructures. This paper evaluates the applicability and effectiveness of Long ShortTerm Memory (LSTM) and Feed-Forward Network (FFN) in detecting DDoS attacks against electric vehicle charging stations through system metrics using CICEV2023 dataset. Experimental results show that the LSTM based model offers advantages in terms of speed and processing capacity, while the FFN is superior in terms of the accuracy.Öğe Investigation of obsessive compulsive disorder with FFT dipol approximation by means of EEG(IEEE, 2015) Özçoban, Mehmet Akif; Aydın, Serap; Kara, Sadık; Tan, OğuzEEG analysis has been used in pathophysiological research of Obsessive Compulsive Disorder (OCD) that is one of the neuropsychiatric disease. EEG abnormalities was observed in brain cortex of patients with OCD. Fast Fourier Transform (FFT) Dipol Approximation Method (FFTDA), used for source localization and superior to conventional FFT method, has also been used for measurement of the level of EEG synchronization. In this research, phase differences between cortical neural oscillations was computed by using FFTDA. Then, analysis of 19 channel EEG series, collected with international 10-20 electrode placement system, shows the loss of Theta band phase synchronization in patients with OCD.Öğe An alternative supplemental feeding method for preterm infants: the supplemental feeding tube device(Tubitak Scientific & Technological Research Council Turkey, 2021) Çalıkuşu İncekar, Müjde; Çağlar, Seda; Kaya Narter, Fatma; Tercan Tarakçı, Emriye; Özpınar, Emine; Demirci Ecevit, EsraBackground/aim: The purpose of this study was to determine the effects of the supplemental feeding tube device (SFTD) and bottle methods on weight gain, transition to full breastfeeding, breastfeeding success, and duration of discharge in preterm infants. Materials and methods: This randomized controlled trial was conducted with a total of 46 preterm infants including 23 infants in study (SFTD) and control (bottle) groups. An information form, an infant follow-up form for feeding, and LATCH breastfeeding assessment instrument were used to collect the data. Results: The gestation week of the infants in the study group was 31.22 +/- 2.76, and in the control group it was 30.52 +/- 2.47. The birth weight of the infants in the study group was 1586.3 +/- 525.35 g and 1506.09 +/- 454.77 g in the control group. The daily weight gain of the infants was 24.09 +/- 15.21 g in the study group and 27.17 +/- 17.63 g in the control group. The infants in the study group (4.70 +/- 2.44 days) transitioned to full breastfeeding earlier than those in the control group (6.00 +/- 4.10 days). LATCH 2nd measurement scores were significantly higher in both groups than LATCH 1st measurement scores (p < 0.01). Although it was not statistically significant (p > 0.05), the infants in the study group (10.22 +/- 5.20 days) were discharged earlier than those in the control group (13.48 +/- 8.78 days). Conclusion: The SFTD and bottle methods were determined to be similar in terms of daily weight gain, transition to full breastfeeding, breastfeeding success, and duration of hospitalization.Öğe Dimensional accuracy analysis of samples printed in delta and cartesian kinematic three dimensional printers(Gazi University, 2021) İncekar, Erkan; Kaygısız, Hüseyin; Babur, SebahattinThe motion mechanisms of manufacturing and robotic systems are developed in different structures, mainly in cartesian and delta structures having series or parallel movement abilities according to the capacity and construction structure of the system. Different systems are used according to the criteria such as bearing load capacity, sensitivity or cost of the system. In this study, the performances of machines installed in the delta and cartesian kinematic structures, which are mostly used in the kinematic systems of three - dimensional printers, were analyzed. In this context, in two different machines with these two construction structures, the same boundary conditions and 4 pieces of calibration parts especially in manufacturing features were printed. 23 different elements that constituted the calibration part were measured, tabulated, statistically analyzed, and the acceptable measuremental tolerance ranges of the elements were determined and the accuracy values of the machines were compared. As a result of this study, according to T test results, 15 of the 23 measurements on the Cartesian system based three-dimensional printers were obtained as acceptable in terms of tolerance range as well as 9 of the 23 different measurements were obtained as acceptable on Delta system. Consequently, operation accuracy of the Cartesian system based three-dimensional printers were higher than the Delta system under the same working conditions and manufacturing parameters.Öğe Synthesis of new regioisomers of 5-Nitro-1,4-Naphthoquinone, evaluation of antioxidant and catalase inhibition activities(Slovensko Kemijsko Drustvo, 2022) Abdassalam, Aesha Fsh; Deniz, Nahide Gülşah; Sayil, Çiğdem; Özyürek, Mustafa; Yeşil, Emin Ahmet; Salihoğlu, HüseyinThe studies on nitronaphthoquinone derivatives are rare in the literature, and the nitro group associated with the aromatic ring in the quinone system is known to increase the biological activity of naphthoquinone due to its electron-withdrawing properties. In the course of quinone derivatives, the new N(H)-substituted-5-nitro-1,4-naphthoquinones (NQ) as regioisomers were synthesized by reactions of 2,3-dichloro-5-nitro-1,4-naphthoquinone with some heterocyclic ring substituted nucleophiles such as anilines, piperazines, or morpholines, according to a Michael 1,4-addition mechanism. Five NQ regioisomer couples having different functional group (2-chloro-isomers 3, 5, 7, 9 and 13; 3-chloro-isomers 2, 4, 6, 8 and 12) are reported here. All new synthesized compounds were characterized by spectroscopic methods and two-dimensional NMR techniques H-1-H-1 correlated spectroscopy (COSY). The synthesized NQ regioisomers were evaluated for catalase enzyme inhibitory activities and antioxidant efficiency. The synthesized regioisomers were screened for their antioxidant capacity using the cupric-reducing antioxidant capacity (CUPRAC) method. 2-Chloro-3-((2,4-dimethoxyphenyl)amino)-5-nitronaphthalene-1,4-dione (5) showed the highest antioxidant capacity with a 1.80 +/- 0.06 CUPRAC-trolox equivalent antioxidant capacity (TEAC) coefficient. Compound 5 also showed strongest catalase enzyme inhibitory activity. The antioxidant capacity results of all 2-chloro regioisomers are higher than the 3-chloro regioisomers. Likewise, also catalase enzyme inhibitory activities results were determined in the same way, except for one regioisomer pair. The catalase was effectively inhibited by the newly synthesized compounds, with % inhibition values in the range of 0.71-0.86%. Some of these NQ compounds also showed remarkable antioxidant capacities.Öğe A bio-based and non-toxic polyurethane film derived from Luffa cylindrica cellulose and L-Lysine diisocyanate ethyl ester(Pergamon-Elsevier Science Ltd, 2021) Akay, Özge; Altınkök, Çağatay; Açık, Gökhan; Yüce, Hüseyin; Konuk Ege, GözdeThis study aims to explore the step-growth polymerization (SGP) between the most abundant biomass-cellulose (LCC) extracted from Luffa cylindrica (LC) and L-Lysine diisocyanate ethyl ester (L-LDI) to be achieved an unprecedented polyurethane network (PUR). The resulting bio-based and non-toxic PUR film is obtained by direct solution casting after SGP. The efficiency of the SGP is examined in detail Fourier transform infrared (FT-IR) and proton nuclear magnetic resonance (H-1 NMR) spectroscopies, water contact angle (WCA) measurements, thermogravimetric and differential scanning calorimetry analyses (TGA and DSC) by comparing precursors and final film. Moreover, the biodegradation behavior of PUR achieved is evaluated in vitro both hydrolytic and enzymatic media. Based on the conducted analyses, PUR film shows higher hydrophobicity and degradation temperatures compared to raw LC and LCC. Moreover, it is determined that the PUR film more degradable than its precursors in both hydrolytic and enzymatic media. Consequently, the approach developed here is broadly adaptable to other functional isocyanate monomers and will be useful to scientists working on bioplastic applications.
