Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Uzun, Sevda(67)
- Merdan, Mehmet(59)
- Duran, Celal(49)
- Ozdes, Duygu(46)
- Kaygusuz, Abdullah(45)
- Demir, Selim(37)
- Turan, Ibrahim(37)
- Karsli, Orhan(36)
- Öztürk, Serkan(35)
- Dokuz, Abdurrahman(34)
- Araz, Onur(32)
- Kandemir, Raif(31)
- Kulakaç, Nurşen(29)
- Sipahi, Ferkan(29)
- Arslan, Mehmet(27)
- Baltaci, Cemalettin(27)
- Baltacı, Cemalettin(27)
- Kurt, Kemal(27)
- Topal, Fevzi(27)
- Gücer, Mehmet Ali(25)
- Peker, Iskender(25)
- Aydin, Faruk(24)
- Bayrakdaroglu, Serdar(24)
- Maden, Nafiz(24)
- Ozturk, Samet(24)
- Vural, Alaaddin(24)
- Yolcu, Halil(24)
- Yücel, Cem(24)
- Aliyazicioglu, Yuksel(23)
- Kankal, Murat(23)
- Reis, Hatice Catal(23)
- Ürkek, Bayram(23)
- Günen, Mehmet Akif(22)
- Kurnaz, Muammer(22)
- Topal, Meryem(22)
- Karimullah, Suud Sarim(21)
- Uysal, Ibrahim(21)
- Ashyralyyev, Charyyar(20)
- Aydin, Aydanur(20)
- Bayraktar, Alemdar(20)
Yayınlar
- MakaleAçık Erişim2023Scopus SJRQ2Strength Analysis in Bonded, Bolted and Bolted-Bonded Joints, Single Lap Joints, Metal/Composite Plates
Sadık, Ali; Karabudak, Filiz
Today, especially in many fields that require structural durability, such as the aerospace and automotive industries, there has been a need to use different bonding techniques separately or together in order to use materials together with different mechanical properties. In this study, stress and damage analysis of single lap joints, bonding and bolt-bonding metal/composite joints under tensile loads were performed. The nine kinds of single lap joint models in different combinations (bonded, bolted and bolt-bonded) were prepared by using acrylic adhesive (Acrytron 1E1) and 100-25-3 mm in size; AZ91/AZ91, AZ91-carbon fiber and carbon fiber-carbon fiber plates. Some comparisons were carried out by examining the stresses and deformations that occur in joint models exposed to tensile and 4-point bending tests. As a result of the tensile test, it was determined that the highest maximum tensile stress occurred in AZ91-CF bolt-bonded samples. In the four-point bending test, the maximum shear force value was determined in the CF-CF bolted-bonded samples.
AtıfScopus10WoS9OpenAlex9
İncele - MakaleYalnız künye2023Scopus SJRQ1Detection of forest fire using deep convolutional neural networks with transfer learning approach[Formula presented]
Reis, Hatice Catal; Turk, Veysel
Forest fires caused by natural causes such as climate change, temperature increase, lightning strikes, volcanic activity or human effects are among the world's most dangerous, deadly, and destructive disasters. Detection, prevention, and extinguishing forest fires is challenging. In addition, forest fires can cause habitat destruction that cannot be controlled in time and cause great material and moral losses. Therefore, fast and accurate Detection of forest fires is vital in emergency response. Here, in solving the problem, the transfer learning method from deep learning sub-topics can be used, which allows the application of pre-trained networks to a new problem. The Fire Luminosity Airborne-based Machine learning Evaluation dataset (consisting of forest fire images) obtained by Unmanned Aerial Vehicle was used in this study. In the Detection of forest fire images in the dataset, InceptionV3, DenseNet121, ResNet50V2, NASNetMobile, VGG-19 deep learning algorithms, transfer learning techniques that can produce more successful results than networks trained from scratch, and hybrid proposed with Support Vector Machine, Random Forest, Bidirectional Long Short-Term Memory, Gated Recurrent Unit algorithms methods have been applied. In the classification study with the Fire Luminosity Airborne-based Machine learning Evaluation dataset in performance measurement, 97.95% accuracy was obtained from the DenseNet121 model, which was started with random weights. In the transfer learning study using ImageNet weights, satisfactory results were obtained with 99.32% accuracy in the DenseNet121 model. We anticipate that working in forest fire detection and response can be entirely satisfactory.
AtıfScopus87WoS64OpenAlex92İncele - MakaleYayıncıda açık erişim2023Scopus SJRQ1MediNet: transfer learning approach with MediNet medical visual database
Reis, Hatice Catal; Turk, Veysel; Khoshelham, Kourosh; Kaya, Serhat
The rapid development of machine learning has increased interest in the use of deep learning methods in medical research. Deep learning in the medical field is used in disease detection and classification problems in the clinical decision-making process. Large amounts of labeled datasets are often required to train deep neural networks; however, in the medical field, the lack of a sufficient number of images in datasets and the difficulties encountered during data collection are among the main problems. In this study, we propose MediNet, a new 10-class visual dataset consisting of Rontgen (X-ray), Computed Tomography (CT), Magnetic Resonance Imaging (MRI), Ultrasound, and Histopathological images such as calcaneal normal, calcaneal tumor, colon benign colon adenocarcinoma, brain normal, brain tumor, breast benign, breast malignant, chest normal, chest pneumonia. AlexNet, VGG19-BN, Inception V3, DenseNet 121, ResNet 101, EfficientNet B0, Nested-LSTM + CNN, and proposed RdiNet deep learning algorithms are used in the transfer learning for pre-training and classification application. Transfer learning aims to apply previously learned knowledge in a new task. Seven algorithms were trained with the MediNet dataset, and the models obtained from these algorithms, namely feature vectors, were recorded. Pre-training models were used for classification studies on chest X-ray images, diabetic retinopathy, and Covid-19 datasets with the transfer learning technique. In performance measurement, an accuracy of 94.84% was obtained in the traditional classification study for the InceptionV3 model in the classification study performed on the Chest X-Ray Images dataset, and the accuracy was increased 98.71% after the transfer learning technique was applied. In the Covid-19 dataset, the classification success of the DenseNet121 model before pre-trained was 88%, while the performance after the transfer application with MediNet was 92%. In the Diabetic retinopathy dataset, the classification success of the Nested-LSTM + CNN model before pre-trained was 79.35%, while the classification success was 81.52% after the transfer application with MediNet. The comparison of results obtained from experimental studies observed that the proposed method produced more successful results. Graphical abstract: [Figure not available: see fulltext.]
AtıfScopus16WoS14OpenAlex18
İncele - MakaleAçık Erişim2023Scopus SJRQ3High-cycle fatigue and tensile strength of AZ91 Mg alloy with MAO-epoxy duplex coating
Karabudak, Filiz
In this study, an epoxy layer was formed by the immersion process, on the oxide layer grown by the micro-arc oxidation (MAO) treatment of the AZ91 magnesium alloy, using the thin film sealing technology, and its effect on fatigue and tensile stress under high cycle conditions was investigated. The microstructures of the AZ91 base material, MAO/AZ91 and MAO-epoxy/AZ91 samples, which were subjected to high-cycle fatigue tests and uniaxial static tensile tests, were assessed through the scanning electron microscope (SEM), X-ray diffraction (XRD) mechanical tests, and fatigue and tensile tests. As a result, the MAO-epoxy duplex coating, which has a homogeneous and compact structure, was observed to improve the fatigue limit value/life, yield strength, ultimate tensile strength, and percentage elongation values of the base material significantly.
AtıfScopus2WoS2OpenAlex2İncele - MakaleAçık Erişim2023Assessment of photovoltaic module temperature estimation for four years with four different software; [Dört yıllık fotovoltaik modül sıcaklık tahmininin dört farklı yazılımla değerlendirilmesi]
Tolgay, Doga; Yakut, Muhammet Samet; Ozden, Talat; Akinoglu, Bulent G.
The software used today, on the estimation of module temperature of photovoltaic systems, seem very important to be analyzed. These estimates are crucial in future techno-economic and environmentally friendly analyses of the systems to reach better achievements for future generations. This is very important to reach lifetime analyses of long-term feasibility to find out payback time and the levelized cost of energy. The present work is based on this issue, to test the module temperature estimation formulas used by four commonly used software models, and to determine the most suitable software for temperature analyses of five different photovoltaic modules in Middle Anatolia. Outdoor truthful long-term testing is the main realistic approach to reach fundamental contemplations. After an introductory basic knowledge, the main materials and methods are discussed to enlighten the analysis. The main methodology is given and further prospects are enlightened. Four well-known software are analyzed using four years of outdoor testing of five different photovoltaic modules. Measured ambient temperature and solar irradiance are used in the categorization of the software estimation performances. PV*SOL appears to be superior at low irradiance and ambient temperature, whereas Helioscope appears to be superior overall.
AtıfScopus2İncele - MakaleAçık Erişim2023THE IMPLICATIONS OF ISLAMIC LAW ON THE RIGHTS OF RELIGIOUS MINORITIES IN MUSLIM-MAJORITY COUNTRIES
Karimullah, Suud Sarim
This study aimed to explore the complex implications of Islamic law on the rights of religious minorities in Muslim-majority countries. Through a comprehensive literature analysis, the study summarized information from various relevant text sources. The findings show the complex challenges faced by religious minorities when exercising the rights in Muslim-majority countries. Examining the impact of Islamic law on religious minorities' rights suggests that the legislation could provide a potential basis for protection. However, the interpretation and application of the law varies between countries. Introducing Islamic law into state policies often creates tensions between religious and universal human rights principles, requiring careful efforts to strike a delicate balance. In modern contexts, such as the impact of globalization and information technology, Muslim-majority countries are faced with challenges that prompt constant adaptation to ensure the effective protection of religious minorities’ rights. Therefore, addressing these challenges requires a comprehensive method including legal reform, interreligious dialogue, and community education to ensure that the rights of religious minorities are respected and substantially protected.
AtıfScopus26OpenAlex18İncele - MakaleAçık Erişim2023Scopus SJRQ1Phenolic Constituents, Antioxidant and Antimicrobial Activity and Clustering Analysis of Propolis Samples Based on PCA from Different Regions of Anatolia
Altuntaş, Ümit; Güzel, İsmail; Özçelik, Beraat
This study aimed to evaluate the biochemical composition and biological activity of propolis samples from different regions of Türkiye to characterize and classify 24 Anatolian propolis samples according to their geographical origin. Chemometric techniques, namely, principal component analysis (PCA) and a hierarchical clustering algorithm (HCA), were applied for the first time to all data, including antioxidant capacity, individual phenolic constituents, and the antimicrobial activity of propolis to reveal the possible clustering of Anatolian propolis samples according to their geographical origin. As a result, the total phenolic content (TPC) of the propolis samples varied from 16.73 to 125.83 mg gallic acid equivalent per gram (GAE/g) sample, while the number of total flavonoids varied from 57.98 to 327.38 mg quercetin equivalent per gram (QE/g) sample. The identified constituents of propolis were phenolic/aromatic acids (chlorogenic acid, caffeic acid, p-coumaric acid, ferulic acid, and trans-cinnamic acid), phenolic aldehyde (vanillin), and flavonoids (pinocembrin, kaempferol, pinobanksin, and apigenin). This study has shown that the application of the PCA chemometric method to the biochemical composition and biological activity of propolis allows for the successful clustering of Anatolian propolis samples from different regions of Türkiye, except for samples from the Black Sea region.
AtıfScopus47WoS44OpenAlex54İncele - MakaleYalnız künye2023Scopus SJRQ2Use of multi-objective examination model to sensitivity analysis for sustainability with three new practices
Şimşek, Ahmet Bahadır
Purpose: The study has two main objectives. The first is to introduce three new examination policy practices: overbooked exam rooms, a substitute invigilator and an inheritance of the invigilation distribution. The second is the use of the examination model to determine the sustainability of the system against expected changes and to obtain long-term strategic information. This study aims to obtain managerial insights on the sustainability of the examination system with the newly introduced practices; it does not claim to propose solutions for large-scale problems. Design/methodology/approach: This study introduces a multi-objective mathematical model that contains a couple of constraints that belong to new practices. To check the sustainability of the system, this study gets help from sensitivity analysis, which informs the decision-maker about how the results will react to parameter changes. The authors perform all experiments in the Python/Gurobi modeling environment. Findings: The results demonstrate that the proposed practices are effective in the efficient use of resources. Also, this study shows that the examination model can be used as a stress test so that the weaknesses of the system can be identified and long-term strategic information can be obtained. Originality/value: The contribution of this study is twofold: the introduction of examination policy practices that are overbooked exam rooms, a substitute invigilator and an inheritance of the invigilation distribution. Overbooked exam rooms aim to use resources effectively, taking into account the possibility of temporarily increasing the exam room capacity. The substitute invigilator protects the examination process against sudden events. The inheritance of the invigilation distribution helps to ensure fairness; and the use of the examination model to obtain managerial insights on expectations. This allows testing the validity of existing policies and making necessary changes, taking into account possible changes in the system. In this respect, it differs from the studies in the literature and fills an important managerial gap.
AtıfScopus1İncele - MakaleAçık Erişim2023Investigation of the structural damage caused by blasting activities in tunnels to surrounding buildings: The case of Gümüşhane belt highway; [Tünellerde patlatma faaliyetlerinin çevre binalara verdiği yapısal hasarın incelenmesi: Gümüşhane çevre yolu örneği]
Seferoğlu, Mehmet Tevfik; Seferoğlu, Ayşegül Güneş; Akaryali, Enver
Tunnels are road transport structures that reduce traffic and expropriation problems, noise, and possible damage to animals and plants, and provide safer, more comfortable, and faster transportation for vehicles compared to highways. However, some environmental problems occur during tunnel construction. These problems such as vibration, noise, rock throwing, etc. caused by the blasting process used during tunnel excavation on buildings and people should be well investigated. In this study, two buildings located close to the exit and entrance of two tunnels (T2 and T3 tunnels) on the Gümüşhane belt road were chosen to investigate. Firstly, the existing damages in the first building, which is 7 m away from the T2 tunnel exit, and the second building, which is 60 m away from the T3 tunnel entrance, were analyzed by considering criteria such as the geological and ground condition of the land and the building materials used during the construction of those building. In addition, the negative effects on the buildings were evaluated by calculating the vibrations after the blasting process in the tunnel with the help of various empirical formulas. Investigation on site showed that building 1 was built of masonry and building 2 was built of reinforced concrete, and that deep cracks had formed in the bearing systems of both buildings, spills occurred in the walls, and fractures in the windows. Also, calculations with empirical formulas showed that the vibration rates caused by blasting process in the 1st and 2nd buildings were as 385.68 mm/sec and 6.91 mm/sec, respectively, and these vibration values were above the standard values. The data obtained through examination on-site and empirical approaches show that it would be dangerous for people to be resident in both buildings.
AtıfScopus3OpenAlex1TR Dizin1
İncele - MakaleYalnız künye2023Scopus SJRQ1Fixed-time neuro-sliding mode controller design for quadrotor UAV transporting a suspended payload
Bingöl, Özhan; Güzey, Hacı Mehmet
This study develops a fixed-time neuro-sliding mode controller to enhance the transient response and robustness of a quadrotor that is subjected to external disturbances and parameter uncertainties along with the dynamics of a suspended payload. A simple neural network with a fixed-time adaptive law is used to estimate unknown dynamics; therefore, no previous knowledge of dynamics is required to develop controllers. The neural network component will also help to eliminate the chattering effect of the sliding mode controller through its learning structure. Fixed-time convergence to desired trajectories is proven by detailed theoretical analysis based on the Lyapunov stability theorem, and to show the proposed controller's effective performance, thorough numerical simulations are run.
AtıfScopus31WoS26OpenAlex28İncele - MakaleYalnız künye2023Scopus SJRQ2Bioactive properties of vinegars produced from prunus laurocerasus L. varieties
Yilmaz, Kubra; Baltaci, Cemalettin; Ozturk, Seyda; Karpuz, Omer
BACKGROUND: Cherry laurel fruit (CLF) has distinctive bioactive properties, which may yield new food products based on CLF. OBJECTIVE: This research aimed to realize the production of vinegar from the CLF, thus, valorizing the CLF, which is rich in antioxidants and phenolic substances, and bringing a new nutrient-rich vinegar to the market. METHODS: Seven types of traditional CLF vinegar (CLFV) from three different species were produced, and their bioactive properties were examined. The bioactivity analyses of total phenolic substance (TPC), total flavonoid (TFC), total antioxidant activity (AA), DPPH (Free radical scavenging activity), FRAP (Ferric reducing antioxidant power), ABTS + (Radical cation scavenging effect) were conducted. In addition, the composition of phenolic substances was studied. RESULTS: This study showed that CLFV performed better than controls regarding antioxidant activity, phenolic compounds, and substances. The presence of intense phenolic elements in CLFV significantly impacts its antioxidant activity. The antioxidant activities of CLFV were detected to be greater than the previous reports on bioactivities of vinegar from various fruits. CONCLUSIONS: High antioxidant and phenolic content were observed in CLFV, similar to the composition of the CLF. The usability of CLFV as a healthy and nutritious food product seems achievable on an industrial scale.
AtıfScopus13WoS12OpenAlex8İncele - MakaleYalnız künye2023Scopus SJRQ1The Association Between Personal, Affective, and Cognitive Factors and Suicide Risk Among Muslims in Turkey
Yazıcı Çelebi, Gülin; Kaya, Feridun
This study was conducted to examine the association of various personal, affective, and cognitive factors with suicide risk. The study group consisted of a total of 423 individuals, including 341 (74%) females and 82 (26%) males, who lived in Turkey and declared that they were Muslims. The data of the study, in which a cross-sectional design was employed, were collected between October and December 2022. The mean age of the participants was 26.84 years (SD = 9.88, min–max = 18–64). The data collection measures included the Psychological Distress Scale, the Perception of God Scale, the Two-Dimensional Self-Esteem Scale, the Suicide Probability Scale, and a personal information form. Pearson correlation analysis and Hierarchical Multiple Linear Regression analysis were employed in the analysis of the data obtained from the research. In the study, it was found that gender, age, suicide attempt, communication with the mother, communication with the father, psychological distress, self-esteem, and perception of God explained 58% of the variance in suicide risk. Psychological distress had the strongest positive association with suicide risk (β = 0.136, p < 0.001), while self-esteem had the strongest negative relation (β = − 0.454, p < 0.001). In conclusion, it was determined that the female gender, suicide attempt, and psychological distress increased the risk of suicide, but that age, positive communication with parents, self-esteem, and positive perception of God decreased it. The findings of the research were discussed in light of the literature.
AtıfScopus2WoS2OpenAlex4İncele - MakaleAçık Erişim2023Shear strength estimations and shear designs on RC beams with limited ductility by FL and FIL methods; [BM ve BTM yöntemleri ile sınırlı sünekliğe sahip betonarme kirişlerde kesme dayanımı tahmini ve kesme tasarımı]
Öztekin, Ertekin
In this study, a fuzzy logic model was constituted by using the Fuzzy Logic (FL) method, which is one of the traditional artificial intelligence (AI) methods, in order to estimate the shear strength of reinforced concrete (RC) beams with limited ductility. In this model, beam width(bw), beam height(h), characteristic concrete compressive strength(fck), transverse reinforcement diameter(ØT), the number of arms bearing the shear force of the transverse reinforcement(n) and transverse reinforcement spacing(s) were taken into account as variable parameters. The model developed by using the problem data containing the solutions of shear force strength of 2640 beams with different cross-section properties were tested with 480 beam solutions different from these data. In the tests of the developed FL model, maximum percentage error, minimum percentage error, average percentage error and correlation coefficient values were obtained as 3.604,-0.091, 1.514 and R2=0.999678. By applying the fuzzy inverse logic method (FIL), which was recently developed by the author of this study, on the FL model, which is seen to have been developed quite sensitively from the test results, a total of 521 designs were obtained for 15 different RC beams with limited ductility subjected to shear. In order to check the accuracy of these designs, after shear strengths were obtained by conventional computations for these designs, % error and correlation coefficients were computed between the obtained strength values and the shear force values taken into account for the design. The promising results show that the FIL method can be used in the design of RC beams under shear force and even in other scientific studies such as design, optimization and control.
AtıfScopus1OpenAlex2İncele - MakaleAçık Erişim2023Scopus SJRQ1Leveraging blockchain in response to a pandemic through disaster risk management: an IF-MCDM framework
Peker, Iskender; Ar, Ilker Murat; Erol, Ismail; Searcy, Cory
The COVID-19 pandemic has underscored the necessity for strategic approaches to manage global catastrophes. This study argues that disaster risk management (DRM) is an essential approach to mitigate the impact of global calamities, such as a pandemic. However, due to the uncertainty emerging from variables such as time and demand, managing DRM effectively involves high complexity. Blockchain technology (BcT) can be implemented to help address these challenges due to its potential to build trust, transparency, and accountability in complex operations. However, no research has quantitatively examined the applicability of BcT in the sub-dimensions of DRM to address the COVID-19 pandemic. The goal and scope of this study is to explore the role of BcT in DRM operations during the COVID-19 pandemic through an Intuitionistic Fuzzy Multi-Criteria Decision Making (IF-MCDM) framework. More specifically, the Intuitionistic Fuzzy Analytic Network Process (IF-ANP) method was utilized to calculate the weights of key criteria (i.e., BcT benefits), while Intuitionistic Fuzzy VIKOR (IF-VIKOR) was used to prioritize the alternatives (i.e., the sub-dimensions of DRM). The findings of this study are threefold. First, supporting effective coordination turned out to be the most essential benefit of BcT to build resilience in response to the COVID-19 pandemic. Second, disaster management was found to be the most appropriate DRM sub-dimension for possible BcT implementation during the COVID-19 pandemic. Lastly, eleven distinct activities involved in disaster management and governance and financial protection were discovered to be the most applicable for BcT. The findings of this study could assist disaster risk managers to assess whether (or not) BcT is suitable for the sub-dimensions of DRM to build national and organizational resilience in the wake of the COVID-19 pandemic.
AtıfScopus27WoS22OpenAlex34İncele - MakaleAçık Erişim2023Scopus SJRQ1The psychological dimension of menopause: a phenomenological study: Being menopause in Turkey: a qualitative study
Uzun, Sevda; Ozcan, Handan; Jones, Duygu
This study aims to determine the perceptions of women in menopause living in Turkey regarding this period and associated problems, which has shown that some women are negatively affected by the menopause period and have difficulty coping with the effects of menopause. The study has a basic qualitative research design, and the sample was determined by using the criterion sampling method, one of the purposeful sampling methods. The effects and characteristics of menopause themes are included in the category of perception of menopause among women, and the themes of positive and negative perspectives are included in the category of perspective on menopause. It is reported that women experience feelings of fear, uncertainty, irritability, anxiety/worry, introversion, relaxation, and happiness during menopause. Our study has shown that some women are negatively affected by the menopause period and have difficulty coping with the effects of menopause.
AtıfScopus4WoS6OpenAlex6İncele - MakaleYalnız künye2023Scopus SJRQ2Natural Walls of Anatolia: formation and development of Diş Kayalıkları as a structural landform (Sivas, Türkiye)
Uzun, Ali; Aylar, Faruk; Zeybek, Halil İbrahim; Gürgöze, Serkan; Bahadir, Muhammet; Alemdağ, Selçuk
The Diş Kayalıkları is one of the largest and most striking examples of crests in the world and is located between Eskidere and Boğazören villages of the İmranlı district of the Sivas province in Türkiye. The crests, which resemble castle walls when viewed from afar, have a real wall pattern due to the right-angled crack system of the bedrock when viewed closely. This study aims at investigating the geomorphological features of the Diş Kayalıkları and determining how the geological and geomorphological evolution of the Diş Kayalıkları took place and how the current formation mechanism continues. In the region, the mid-latitude continental climate prevails with cold humid winters and warm dry summers. The bedrock consists of Miocene bedded deposits of different resistance, folded by young tectonic movements. Diş Kayalıkları was formed by selective erosion of less resistant terrain around a pack of resistant rock on the steeper southern slope of an asymmetrical anticline. It has a length of 4750 m in the approximately northwest-southeast direction, a maximum height of 30 m, and a width varying between 5 and 8 m. In the present morphological appearance of the Diş Kayalıkları, it can be stated that the structure formed after the tectonic formation process was eroded under the control of the local climate and crest formation was realized. In the following process, the crest experienced a polycyclic process where different landforms were formed. There are smaller landforms such as karren, cave and rock window on Diş Kayalıkları, and macrofossil beds in some places. This highly attractive geomorphosite, unknown to wider public, should be investigated from various scientific aspects and should be brought to regional tourism by making the necessary infrastructure and promotion studies.
AtıfScopus1WoS2OpenAlex2İncele - MakaleAçık Erişim2023Scopus SJRQ2A green and simplified approach for the quantitative and sensitive analysis of heavy metal ions in sea and stream waters
Duran, Celal; Camoglu, Aslihan Yilmaz; Ozdes, Duygu; Bekircan, Olcay
Elimination of the matrix effect is a major challenge in developing a method for the quantification of heavy metals (HMs) in water samples. In this regard, the current research describes the simultaneous analyses of Cu(II), Cd(II), and Ni(II) ions in water matrices through flame atomic absorption spectrophotometry (FAAS) after preconcentration with carrier element-free co-precipitation (CEFC) technique by the help of an organic co-precipitant, 3-{[5-(4-Chlorobenzyl)-3-(4-chlorophenyl)-1H-1,2,4-triazol-1-yl]-methyl}-4-[2,4-(dichlorobenzylidene)amino]-1H-1,2,4- triazole-5(4H)-thione (CCMBATT). Based on our literature research, CCMBATT was employed for the first time in this study as an organic co-precipitant for the preconcentration of HMs. Factors such as solution pH, concentration of co-precipitant, sample volume, standing time, centrifugation rate, and time were thoroughly examined and optimized to achieve the highest efficiency in terms of HM recovery. The limits of detection (LODs) (with 10 number of tests) of 0.54, 0.34, and 1.95 μg L-1 and the relative standard deviations (RSD %) of 2.1, 3.3, and 3.0 were determined for Cu(II), Cd(II) and Ni(II) ions, respectively. Recovery results of HMs for the spiked samples were in the range of 92.8-101.0%, demonstrating the trueness of the method and its applicability to the water samples matrix.
AtıfScopus2WoS2OpenAlex1İncele - MakaleAçık Erişim2023Scopus SJRQ1Performance analysis of digitally controlled nonlinear systems considering time delay issues
Yanarateş, Cağfer; Okur, Serkan; Altan, Aytaç
In this paper, a comprehensive investigation into discretization, effective sample time selection considering delays in the system, and time and frequency domain analysis of a DC-DC buck converter, which plays a vital role in photovoltaic (PV) systems, is conducted to enhance the understanding of their dynamic behavior, optimize control algorithms, improve system efficiency, and ensure reliable power conversion in photovoltaic applications. To effectively address the non-linear behavior and enhance digital control of a buck converter by selecting the best sample time, several approaches can be employed. These include accurate modeling and identification of non-linear elements, development of advanced control algorithms that account for non-linearities, implementation of adaptive control techniques, and utilization of feedback mechanisms to compensate for deviations from linearity. By considering and mitigating the non-linear behavior, digital control systems can achieve improved accuracy, stability, and transient behavior in regulating the buck converter's output waveforms (voltage or current). The results of the study demonstrated that the trapezoidal integration method which is also known as bilinear approximation, or Tustin's approach outperformed other commonly used discretization methods, such as first-order hold (FOH), zero-order hold (ZOH), impulse response matching (impulse invariant), and matched pole-zero (MPZ) technique, in dual-domain (both time and frequency) analysis. The key finding highlighting the superiority of the bilinear approximation was its ability to achieve the closest match in the frequency domain bridging the continuous-time and discrete systems. This finding emphasizes the significance of the bilinear approach in preserving the frequency characteristics of the original continuous-time system during discretization. By employing this method, the discrete system closely approximated the behavior of its continuous-time counterpart, ensuring accurate frequency-domain representation.
AtıfScopus60WoS57OpenAlex58İncele - MakaleAçık Erişim2023First report of qnr and blaVIM-4-like producing clinical Alcaligenes faecalis isolated in Türkiye; [Türkiye'den izole edilen qnr ve blaVIM-4-like üreten klinik Alcaligenes faecalis’in ilk raporu]
Akyildiz, Esma; Saral Sariyer, Ayşegül; Köse, Tuba; Arslan, Mikail; Beriş, Fatih Şaban; Özad Düzgün, Azer
The study set out to look at the clinical strain of A. faecalis's antibiotic susceptibility pattern. Both biochemical and molecular approaches were used to identify A.faecalis. The VITEK compact system was used to analyze the strain's antibiotic susceptibility profile. The use of PCR was evaluated to determine the presence of resistance genes. It was also determined whether resistance determinants could be transferred. It was determined that A. feacalis showed resistance to imipenem, cefepime, ceftazidime, gentamicin, amikacin, netilmicin, tobramicin, ciprofloxacin, and levofloxacin. The blaVIM-4-like gene was present in this strain, according to the results of the PCR and DNA sequencing studies. In contrast to VIM-4, this blaVIM-4-like gene showed one amino acid change (Ala265Val).Filter-mating experiments showed that the blaVIM-4-like gene cannot be transferred from A. faecalis to E. coli. In this study, This research, demonstrated the presence of the blaVIM-4-like gene for the first time in A. faecalis from Turkey.
- MakaleAçık Erişim2023Effect of aging time and temperature on properties of AA7075 alloy; [Yaşlandırma süresinin ve sıcaklığının AA7075 alaşımının özelliklerine etkisi]
Budak, Selahattin; Çolak, Harun; Yakut, Yusuf
In this study, the effect of aging at different temperatures and times on the properties of AA7075-T6 alloy was investigated. The samples prepared for the experimental studies were subjected to the solution, quenching, and then aging heat treatment at 100 °C and 200 °C for different periods (42-66-90 hours). The properties of the experimental samples were investigated by hardness, compression test, and scanning electron microscope (SEM). As a result of the studies, it was determined that the aging heat treatment had a positive effect on the microstructure and mechanical properties of the AA7075 alloy compared to the reference sample. Especially as a result of the heat treatments at 100 °C, higher results were obtained in hardness and compression strength compared to the initial values.
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