Gümüşhane ÜniversitesiGümüşhane ÜniversitesiAçık Erişim Arşivi · RDL Open

Sürdürülebilir Kalkınma Amaçları

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Yeniden eskiyeEskiden yeniye
  • MakaleAçık Erişim2023
    Determination of Elemental Contents and Microbiological and Chemical Properties of Çökelek Cheeses Consumed in Turkey

    Kalaycı, Nagihan; Ürkek, Bayram; Öztürk, Feyza; Şengül, Mustafa; Çiftçi, Esengül

    The Çökelek samples what 30 different were collected from randomly local bazaars to investigate heavy metal contaminant and mineral levels and some physicochemical and microbiological properties of samples. While the Pb was identified in 6 of the 30 samples, the As was only found in 4 of the samples. The mean major and trace element contents of Çökelek samples were ordered as Na > P > Ca > K > Mg and Al > Zn > Ni > Cu, respectively. The physicochemical properties indicated a high deviation among samples. The mean total solids, ash, salt, fat, protein waters soluble nitrogen contents, and sample ripening index were 29.83%, 1.88%, 0.68%, 4.31%, 19.84%, 0.33%, and 1.79%, respectively. The mean total aerobic mesophilic bacteria (TAMB) count of Çökelek samples was found as 8.26 log CFU g−1. The coliform bacteria and yeast-mold counts were detected in 11 and 27 of 30 samples, respectively. The mean coliform and yeast-mold counts were 1.82 log CFU g−1 and 7.11 log CFU g−1, respectively. Traditional cheeses are not mentioned in legal laws such as the Turkish Food Codex. So, there is no legal limit and standard production processes. This situation is a problem in terms of traditional cheese quality. For this reason, traditional cheese should perform further studied, and determine the legal limits.

    • SDG 2 · Açlığa Son
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  • MakaleYalnız künye2023
    Economic and Institutional Determinants of Corruption: The Case of Developed and Developing Countries

    Acaravci, Ali; Artan, Seyfettin; Hayaloglu, Pinar; Erdogan, Sinan

    Since ancient times, corruption has been one of the essential topics for economists and politicians. Moreover, it is a concern for both developed and developing countries and a significant obstacle to economic development. The primary objective of this paper is to examine the relationships between corruption, economic growth, internet use, and quality of governance alongside other institutional and economic variables in 65 developed and developing countries for the period 1999–2016 by using dynamic panel data methods performing well under cross-sectional dependence. The empirical results can be summarized as follows. The augmented mean group (AMG) results indicate statistically significant relationships between corruption, economic growth, internet use, quality of government, and democracy. Also, we find that an increase in economic growth and quality of governance contribute to reducing corruption in these 65 developed and developing countries. In contrast, an increase in internet use and democracy level raises corruption. The policy implications of the empirical estimations are also discussed in the paper.

    • SDG 8 · İnsana Yakışır İş ve Ekonomik Büyüme
    • SDG 16 · Barış, Adalet ve Güçlü Kurumlar
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  • MakaleAçık Erişim2023
    Highly Efficient Spectrophotometric Determination of Cu2+ ion in Aqueous Medium Using a thiosemicarbazone–derivative Ligand

    Başoğlu, Aysel; Ocak, Ümmühan; Iyidoğan, Ayşegül Karaküçük

    A new simple spectrophotometric method for the determination of Cu2+ ion was developed using an thiosemicarbazone compound, 2-{4-[Bis(2-chloroethyl)amino]benzylidene}-N-[(4-methylthio)phenyl]hydrazinecarbothioamide (TSC). A simultaneous color change was observed (from colorless to bright yellow) by the addition of Cu2+ ion to the TSC ligand solution. The maximum absorbance of the TSC ligand measured at 366 nm was decreased by the presence of Cu2+ ion. The graphs of absorbance obtained by means of the Job’s method and the molar-ratio method proposed a complex formation with a 1:2 Cu2+–TSC ligand stoichiometry. The molar-ratio method with emission measurements also confirmed the stoichiometry. The complex stability constant of TSC–Cu2+ complex (K) was evaluated to be 1.76 × 105. The proposed spectrophotometric method was associated with the change in absorbance at 366 nm owing to the interaction between the TSC ligand and Cu2+ ion. From the spectrophotometric titration data, it was pointed out that TSC ligand (1.5 × 10− 5 mol L-1) selectively reacted with Cu2+ ion in DMSO/water (1:1, v/v, citrate buffer at pH = 6.0). The calibration curve for Cu2+ ion was obtained with a good linearity in the range of 0.0191–0.3241 mg L-1. The detection limit for Cu2+ ion was 0.0063 mg L-1. The proposed method was achievemently implemented in real water samples (drink water, tap water and, distilled water). Satisfactory recoveries were confirmed at three different concentrations. The method presented a relative standard deviation (RSD%) of less than 3.08%.

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  • MakaleYalnız künye2023
    Climatic Niche Divergence and Conservatism Promote Speciation in Snake-Eyed Skinks (Sauria: Scincidae): New Insight into the Evolution and Diversification of Ablepharus Species

    Vaissi, Somaye; Kurnaz, Muammer; Şahin, Mehmet Kürşat; Hernandez, Axel

    The degree to which closely related species conserve or diverge in their niche characteristics may provide insight into evolutionary and diversification processes, as well as some understanding of broad-scale biogeographic patterns. In this study, we used an ensemble of 10 algorithms to predict the distributions of 12 Ablepharus species in geographical (G)-space for the recent time and the future (2081–2100) climate conditions. Niche overlap, equivalency, and similarity tests in environmental (E)-space were used to test niche divergence and conservatism. The consensus model showed that temperature seasonality (n = 6) and annual precipitation (n = 3) were the major factors predicting the distribution of 75% (9 out of 12) of the species. The ensemble models based on ssp585 predict that 83.33% of the species (n = 10) may have contracted their ranges, especially at lower altitudes along their southern margins. They may have also expanded northward during this period. However, in the ssp126, most species’ distribution ranges may remain unchanged despite contractions and expansions. Based on multivariate niche analyses, the distributions of 28 and 11 paired comparisons explored in this study significantly diverged and conserved. We found that closely related species inhabit different habitats and respond to their climatic characteristics, indicating that ecology has a significant influence on speciation.

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  • MakaleAçık Erişim2023
    Testing the Short, Medium, and Long-Term Effects of Shocks on Ecological Balance

    Yilanci, Veli; Adali, Zafer; Çelik, Orkun; Bari, Bilgin

    Ecological balance is an indicator of environmental degradation, which is computed as the difference between biocapacity and ecological footprint. In this study, we examine whether the effect of shocks on the ecological balance is permanent or temporary in the EU-15 countries, considering the period from 1961 to 2018. The application of unit root tests, with and without a Fourier function, indicates that the effects of shocks are temporary in only four countries. To reveal the persistence of shocks at different frequencies, that is, the short-, medium-, and long-run, we decomposed the ecological balance series by using the Discrete Wavelet Transform method. The unit root test results show that the effects of shocks are temporary in all countries in the short-run. However, the results also show that the shocks are temporary in nine countries in the medium-run and ten countries in the long-run. Thus, the implemented policies to balance ecology are not effective in the short-run but are effective in only six countries in the medium-term and in only five countries in the long-term. These findings demonstrate the importance of considering different frequencies when testing the effectiveness of empirically implemented policies. Regarding policy implications, this study suggests focusing on medium- and long-term environmental policies rather than short-term ones.

    • SDG 15 · Karasal Yaşam
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  • MakaleAçık Erişim2022
    Exploring anxiety levels in healthcare workers during COVID-19 pandemic: Turkey sample

    Şahin, Ceyda Uzun; Kulakaç, Nurşen

    As in the whole world, the Novel Coronavirus (COVID-19) pandemic poses many threats to healthcare workers in our country too, which leads to anxiety in healthcare workers. This study was conducted to explore the anxiety levels of healthcare workers during the COVID-19 pandemic. The study is a cross-sectional study. The population consisted of health care workers employed in hospitals in seven regions in Turkey. All volunteer healthcare workers were included in the study, and 356 healthcare workers responded to the questionnaire. The data were collected using the State Anxiety Inventory and a questionnaire created by the researchers using an online questionnaire between 10 May 2020 and 15 May 2020. In the evaluation of the data, mean, standard deviation, percentages, t-test, one-way ANOVA, Pearson correlation, and multiple regression analysis were used. 33% of healthcare workers did not have anxiety, 50% had mild, and 17% had severe anxiety. The anxiety scores of those who were nurses (p < 0.001), who were working in the emergency room (p < 0.001), who were involved in treatment for COVID-19 patients (p = 0.040), who left their homes to prevent transmission to their families and relatives during the pandemic (p = 0.038), and whose working hours had changed (p = 0.036) were found to be significantly higher. It was observed that there was a positive and significant relationship between the fear of death and disease transmission, uncertainty, loneliness, anger, and hopelessness, and anxiety levels in healthcare workers. The main factors that significantly affected the anxiety levels of healthcare workers were male gender, weekly working hours, the presence of chronic diseases, and feelings of anger and uncertainty. In conclusion, during the COVID-19 pandemic, healthcare workers experienced some negative emotions, their anxiety levels increased, and they were psychologically affected. Planning psychosocial interventions for healthcare workers in the high-risk group will make significant contributions to the health system.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
    • SDG 8 · İnsana Yakışır İş ve Ekonomik Büyüme
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  • MakaleAçık Erişim2022
    Investigation of gamma ray absorption levels of composites produced from copper mine tailings, fly ash, and brick dust

    Külekçi, Gökhan

    To date, heavyweight concretes have been produced from various heavy aggregates as radiation insulation materials, and their gamma ray absorption levels have been investigated. Many of the studies have used heavy aggregates instead of cement or coarse aggregates from composite material components. The present study prepared lightweight concretes using copper mine tailings, clay brick dust, and fly ash instead of fine aggregates. Some mechanical tests (density, compressive strength, and ultrasonic pulse velocity) were performed on composite blocks with dimensions of 5*5*5 cm, and radiation interaction parameters [linear absorption coefficient (cm−1), mass attenuation coefficient (cm2/gr), HVL (half-value layer) (cm), MFP (cm), and permeability (%)] were measured. Radiation interaction parameters were obtained using a HPGe gamma detector. Radiation measurements were performed at five different photon energies: 583 keV (133Ba), 609 keV (133Ba), 662 keV (137Cs), 911 keV (133Ba), 1173 keV (60Co), and 1332 keV (60Co). Additionally, the compressive strength and UPV values of composite materials were associated with their gamma ray permeability. Tests revealed that samples with the addition of copper mine tailings yielded the best energy absorption at all energy levels and that absorption decreased as the energy level increased. For example, with the increasing of the energy level, mass attenuation coefficients decreased. The highest mass attenuation coefficients were obtained as 0.128 cm2/g at an energy level of 583 keV in composites produced from copper mine tailings. On the other hand, it was measured at the same energy level as 0.069 cm2/g (a 46% decrease) in the composites produced with fly ash. In addition, it was observed that fly ash used as a fine aggregate did not have a significant effect on mass attenuation coefficient and could be used as a gamma shield if the material thickness was increased to an average of 14 cm. This study revealed that tailings materials could be used as radiation shields. This study also demonstrated that not using heavy aggregates and producing lightweight concrete in radiation shield production significantly reduced shield production cost.

    • SDG 12 · Sorumlu Üretim ve Tüketim
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  • MakaleYalnız künye2022
    Characterization of the Welding Zone of Automotive Sheets of Different Thickness (DP600 and DP800) Joined by Resistance Spot Welding

    Aydin, Kemal; Hidiroglu, Mehtap; Kahraman, Nizamettin

    Automotive industry in recent years, has gained great importance. In line with this, DP600 and DP800 dual-phase steels and the electrical resistance spot welding method were used in the study. During the experimental trials, different welding currents (6, 7, and 8 kA) were selected and all other welding parameters were kept constant. The effects of the welding parameters on microstructure, hardness, tensile-shear, and cross-tensile strength were analyzed. In the phase measurements, 27.06–29.97% martensite and 70.73–73.85% ferrite phases were found. When the hardness values in the HAZ regions were examined, it was seen that the highest hardness values were 356 ± 5 HV in the DP600 and 451 ± 5 HV in the DP800 with a current intensity of 6 kA. Consequently, it was determined that tensile-shear and cross-tensile strengths had increased in parallel with the increase in the welding current and the highest values were determined as 8 kA–15.91 kN in tensile shear and 8 kA–4.91 kN in cross-tensile strength.

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  • MakaleYayıncıda açık erişim2022
    Analyzing and Predicting Spatiotemporal Urban Sprawl in Eskişehir Using Remote Sensing Data

    Küçük Matcı, Dilek; Çömert, Resul; Avdan, Uğur

    Urban areas of major cities in developing countries are expanding rapidly due to rapid population growth and industrialization. Determining the reasons for rapid urbanization and the amount of urban area that will be needed in the future is important for the planned growth of these cities. In this study, the LU/LC change of Eskisehir city center that has a rapid rate of urbanization and industrialization in Turkey between 1984 and 2020 was determined. Then, the area needed for urban and industrial areas in 2030 was investigated using the Cullullar Automata–Markov Chain (CA–MC) hybrid model simulation. Each year's LU/LC map was produced with over 80% kappa accuracies performing the pixel-based Random Forest (RF) algorithm for change analysis. In the change analysis made between 1984 and 2020, it was determined that there was a change of 117% in the urban area and 977% in the industrial area. The prediction was made for the validation of the CA–MC model from the period 2000–2010 to 2020. When compared with the 2020 LU/LC map, the model success was obtained as 0.84, 0.87, and 0.87 in the Kstandard, Klocation, and Kno Kappa metrics, respectively. By using the 2010–2020 periods in the estimation of 2030, it has been observed that the urban and industrial area will increase by 22.95%; therefore, there will be decreases in agriculture and other natural areas as in previous years.

    • SDG 11 · Sürdürülebilir Şehirler ve Topluluklar
    • SDG 15 · Karasal Yaşam
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  • MakaleAçık Erişim2022
    Revisiting Slotted ALOHA: Density Adaptation in FANETs

    Eroğlu, Alperen; Onur, Ertan

    Unmanned aerial vehicles have been widely used in many areas of life. They communicate with each other or infrastructure to provide ubiquitous coverage or assist cellular and sensor networks. They construct flying ad hoc networks. One of the most significant problems in such networks is communication among them over a shared medium. Using random channel access techniques is a useful solution. Another important problem is that the variations in the density of these networks impact the quality of service and introduce many challenges. This paper presents a novel density-aware technique for flying ad hoc networks. We propose Density-aware Slotted ALOHA Protocol that utilizes slotted ALOHA with a dynamic random access probability determined using network density in a distributed fashion. Compared to the literature, this paper concentrates on proposing a three-dimensional, easily traceable model and stabilize the channel utilization performance of slotted ALOHA with an optimized channel access probability to its maximum theoretical level, 1/e, where e is the Euler’s number. Monte-Carlo simulation results validate the proposed approach leveraging aggregate interference density estimator under the simple path-loss model. We compare our protocol with two existing protocols, which are Slotted ALOHA and Stabilized Slotted ALOHA. Comparison results show that the proposed protocol has 36.78% channel utilization performance; on the other hand, the other protocols have 24.74% and 30.32% channel utilization performances, respectively. Considering the stable results and accuracy, this model is practicable in highly dynamic networks even if the network is sparse or dense under higher mobility and reasonable non-uniform deployments.

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  • DüzeltmeAçık Erişim2022
    Correction to: The First Measurement for Mass Attenuation Coefficients, Effective Atomic Numbers, and Electron Densities of Y123 and Y358 High-Temperature Superconductors (HTS) for the Energies from 46.6 to 1332 keV (Journal of Superconductivity and Novel Magnetism, (2021), 34, 3, (695-703), 10.1007/s10948-020-05771-0)

    Düzgün, İbrahim

    The original version of this article contained a mistake. Thus this erratum is presented to fix this error. The section “Funding” should read as follows: This study was funded by the Grant-in-Aid for Gümüşhane University Research Fund (GÜBAP), from the Gümüşhane University (Project Number: 13.F5120.02.1).

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  • MakaleYalnız künye2022
    In vitro and in silico evaluation of some plant extracts and phytocompounds against multidrug-resistant Gram-negative bacteria

    Aydemir, Eda; Sarıyer, Emrah; Akyıldız, Esma; Özad Düzgün, Azer; Camadan, Yasemin; Saral Sarıyer, Ayşegül

    The spread of multidrug-resistant Gram-negative (MDR) bacteria is a global public health problem, as infections caused by MDR Gram-negative bacteria are difficult to treat. New antibiotic agents need to be developed to overcome this problem, and phytochemicals show promise at this point. In this study, methanol extracts were prepared from cinnamon, thyme, nettle, white tea, rosehip, and antibacterial activity of the methanol extracts was studied against two MDR Gram-Negative bacteria (K. pneumoniae and A. baumannii) by broth microdilution method. The MICs of methanol extracts of cinnamon, rosehip, thyme, white tea for A. baumannii were found as 0.015125 g/ml, 0.07825 g/ml, 0.030625 g/ml, 0.00796875 g/ml, respectively. It was found that only cinnamon methanol extract had antibacterial activity in the used extract concentrations against K. pneumoniae and the MIC value was 0.0605 g/ml. The effects of plant methanol extract with antibacterial activity and imipenem combinations were studied in vitro using the checkerboard method. The FIC Indexes were obtained from the checkerboard results and it was observed that the combination of methanol extract and imipenem showed an antagonistic or additive/indifferent effect but not a synergistic effect. We evaluated the binding affinity of epigallocatechin 3-gallate, quercetin, cinnamaldehyde, carvacrol, and thymol phytocompounds using in silico methods, which are well known as a phytocompounds in white tea, cinnamon, thyme, nettle, and rosehip and have antibacterial activities. The results suggested that these phytocompounds should be supported with in vivo and in vitro experiments to investigate their potential for being inhibitor candidates.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
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  • MakaleYalnız künye2022
    Robust copy-move detection in digital audio forensics based on pitch and modified discrete cosine transform

    Ustubioglu, Beste; Küçükuğurlu, Büşranur; Ulutas, Guzin

    Copy-move forgery is one of the most widely used methods in the field of audio forensic because it is difficult to detect and convenient to apply. However, post-processing operations applied to forged speech to hide traces of forgery make detection of forensic more difficult. In this study, we propose a robust method for detection and localization of the audio copy-move forgery using modified discrete cosine transform (MDCT). For this purpose, we first divide the speech recording into voiced and unvoiced parts by extracting a pitch sequence from the speech recording. After the determination of voiced parts, we extract MDCT coefficients from them and take the mean of the transpose of the coefficient matrix as the feature. These MDCT features are very robust against commonly used post-processing operations (especially audio compressing). Euclidean distance (ED) is applied to compute the similarities between the features. The voiced parts, which give minimum ED are determined as copy-move audio parts. Also, two separate databases (Pitch-based and Voice Activity Detection (VAD-based) are created during the work to evaluate the performance of the proposed method because there is no common database in the field of audio forensic in the literature. Experiment results show that the proposed method gives better results for detection and localization of audio copy-move forgery on different databases compared to other studies in the literature. The proposed method is also robust against common post-processing operations such as noise addition, filtering operation, and especially compression operation.

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  • MakaleAçık Erişim2022
    40Ar–39 Ar dating, whole-rock and Sr-Nd isotope geochemistry of the Middle Eocene calc-alkaline volcanic rocks in the Bayburt area, Eastern Pontides (NE Turkey): Implications for magma evolution in an extension-related setting

    Kaygusuz, Abdullah; Yücel, Cem; Aydınçakır, Emre; Gücer, Mehmet Ali; Ruffet, Gilles

    Discussions continue about whether Middle Eocene magmatism in the Eastern Pontides is associated with collision or subduction. This paper presents new whole-rock geochemistry, Sr-Nd isotopic and 40Ar-39Ar age data for Middle Eocene volcanic rocks from the Bayburt area of the Eastern Pontides (NE Turkey) to investigate their sources and evolutionary history. The new 40Ar–39Ar ages reveal that these volcanic rocks erupted between 44.6 ± 0.1 Ma and 43.5 ± 0.1 Ma, within the Lutetian (Middle Eocene). The studied volcanic rocks are composed of basalt, andesite, basaltic andesite and minor dacite lava and pyroclastic rocks. These rocks consist of plagioclase, amphibole, pyroxene, olivine, biotite, sanidine and minor quartz phenocrysts with Fe-Ti oxides. They have microlithic, hyalo-microlithic, porphyritic and rarely glomeroporphyritic textures. The volcanic rocks have low to high-K calc-alkaline affinities. They display enrichment in large-ion lithophile elements and depletion in high-field strength elements with high Th/Yb ratios, which indicate that the magmas forming the volcanic rocks were derived from lithospheric mantle sources enriched by mostly slab-derived fluids in the spinel stability field. 87Sr/86Sr(i) values vary between 0.70485 and 0.70551 and 143Nd/144Nd(i) values vary between 0.51255 and 0.51267. These data correspond to the mantle array on the isotope ratio diagram. The main solidification processes consist of fractional crystallization with minor assimilation. In light of the data obtained in this study together with data from previous studies, petrogenetic character of the Middle Eocene magmas from the southern parts of the Eastern Pontides may be explained by melting of an enriched lithospheric mantle source initially metasomatized by subduction fluids in a post-collisional extensional-related tectonic setting.

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  • MakaleYalnız künye2021
    Innovative and polygonal trend analyses applications for rainfall data in Vietnam

    Şan, Murat; Akçay, Fatma; Linh, Nguyen Thi Thuy; Kankal, Murat; Pham, Quoc Bao

    It is a known fact that the size, frequency, and spatial variability of hydrometeorological variables will irregularly increase under the impact of climate change. Among the hydrometeorological variables, rainfall is one of the most important. Trend analysis is one of the most effective methods of observing the effects of climate change on rainfall. Recently, new graphical methods have been proposed as an alternative to classical trend analysis methods. Innovative Polygon Trend Analysis (IPTA), which evolved from Innovative Trend Analysis (ITA), is currently one of the proposed methods and it does not contain any assumptions. The aim of this study is to compare IPTA, ITA with the Significance Test and Mann-Kendall (MK) methods. To achieve this, the monthly total rainfall trends of 15 stations in the Vu Gia-Thu Bon River Basin (VGTBRB) of Vietnam have been examined for the period 1979–2016. The analyses show that rainfall tends to increase (decrease) in March (June) at nearly all stations. IPTA and ITA with the Significance Test are more sensitive than MK in determining the trends. While trends were detected in approximately 90% of all months in IPTA and ITA with the Significance Test, this rate was only 23% in the MK test. Although the arithmetic mean graphs in the 1-year hydrometeorological cycle are considerably regular at almost all stations, their standard deviations are relatively irregular. The most critical month for trend transitions between consecutive months for all the stations is October, which has an average trend slope of −1.35 and a trend slope ranging from −3.98 to −0.21, which shows a decreasing trend.

    • SDG 13 · İklim Eylemi
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  • MakaleYalnız künye2021
    Particle Erosion Performance of Additive Manufactured 316L Stainless Steel Materials

    Azakli, Zeki; Gümrük, Recep

    Many critical parts such as surface parts of high-speed trains, bins and hoppers, and pipes, bends and valves in material transportation applications as well as a helicopter, mixer, and turbine blades, which can be exposed to particle wear due to the application environment, can be easily manufactured today due to the advances in 3D printing technology. For this reason, an experimental study was carried out to determine the particle erosion behavior of 316L stainless steel parts built by the laser melting method, which is one of the 3D printing technologies. The rectangular plate samples produced with various laser manufacturing parameters were subjected to particle erosion tests at different impingement angles in accordance with the ASTM G76 standard at 140 m/s impact speed. The results showed that the erosion behavior develops in a characteristic similar to the wrought sample, and laser parameters play an efficient role. For example, the porosity ratio decreases at low scanning speeds, resulting in significant improvements in erosion behavior. Also, it was found that the particle erosion behavior of the 3D printed parts could be improved in a serious amount by applying a heat treatment process. Consequently, the obtained results in this study promotes the more comprehensive works regarding the optimization of several laser manufacturing parameters such as scan speed, build direction, laser power, hatch spacing, layer thickness, scan strategy and laser exposure time to obtain the best particle erosion behavior and determination of the most suitable materials among the several others which can be used in 3D printing.

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  • MakaleYalnız künye2021
    Mineralogical and Chemical Characteristics of Clay Areas, Gümüşhane Region (NE Turkey), and Their Detection Using the Crósta Technique with Landsat 7 and 8 Images

    Vural, Alaaddin; Akpinar, İbrahim; Sipahi, Ferkan

    The clay areas in Gümüşhane (NE Turkey) were examined in mineralogical and geochemical terms, and by remote sensing methods. X-ray diffraction, scanning electron microscope and chemical analysis were completed on samples from 11 selected clay areas in the region. Within the scope of remote sensing, Landsat 7 and 8 satellite images of the region were processed with the Crósta technique to assess the clay areas. The Kale and Tamzı clays are contained within a Late Cretaceous turbiditic series. The clays in Canca, Refene and Çamlıca occur in intensively hydrothermally altered volcanic rocks of the Eocene Alibaba Formation. The other clay areas are in the Liassic Şenköy Formation consisting of a volcano-sedimentary series. The clays in the Şenköy Formation are generally below the coal levels. While mainly illite and lesser kaolinite were determined in Dörtkonak, Alemdar, Yukarı Kov and Çamlıca, the clays in Tahnis and Kabantaşı are smectite. Tekke, Canca and Refene clays are kaolinite with smaller amounts of illite, whereas Kale and Tamzı clays are mainly chlorite with lower content of illite–smectite interlayers. Illites in Dörtkonak, Alemdar, Yukarı Kov and Çamlıca are poor in iron and magnesium and formed by hydrothermal alteration of feldspars in the host rocks. Findings of the remote sensing studies using Landsat 7 and 8 datasets were compatible with the results obtained from field observations and general geological studies, and so it is concluded that the Crósta technique provided good results for exploration of clay occurrences and their determination in the region.

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  • MakaleYalnız künye2021
    The First Measurement for Mass Attenuation Coefficients, Effective Atomic Numbers, and Electron Densities of Y123 and Y358 High-Temperature Superconductors (HTS) for the Energies from 46.6 to 1332 keV

    Düzgün, İbrahim

    Y123 and Y358 high-temperature superconductor phases have experimental mass attenuation coefficients (MAC) determined at 46.5, 81, 122, 302, 356, 383, 662, 1173, and 1332 keV photon energies. The experimental values have been compared with theoretical values acquired employing the XCOM software and database. It has been observed that the theoretical and the empirical results were in perfect agreement. Also, it has been seen that the comparison of the MACs for all specimens examined with the corresponding photon energies complies with the exponential absorption law. The effective atomic numbers (Zeff) and electron densities (Nel) of Y123 and Y358 superconducting phases in different energy ranges have determined experimentally and theoretically. The Y358 superconductor specimen is a relatively better absorber than the Y123 between 40 and 100 keV.

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  • MakaleYalnız künye2021
    The Effect of Grain Growth Temperature on the Trapped Magnetic Field of Y358 Superconductors

    Başoğlu, M.

    In this study, three different Y358 samples were produced by the melt-powder-melt-growth (MPMG) method at different maximum grain growth temperatures of 1030 °C, 1040 °C, and 1050 °C. The differential thermal analysis (DTA), X-ray powder diffraction (XRD), magnetic levitation force, trapped magnetic field values and magnetization measurements were performed. According to the results, the highest magnetic levitation force, the highest critical current density and the highest trapped magnetic field values were obtained from the sample produced at the temperature of 1050 °C.

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  • MakaleYalnız künye2021
    Extraction of Metals from Scrap Marble Cutting Segments in Nitric Acid Solutions

    Celep, Oktay; Orak, Mürsel; Yazici, Ersin Y.; Deveci, Hacı

    Extraction of cobalt, copper, and silver from scrap saw-blade segments using nitric acid solutions (0.1–0.4 M, 20–60°C) were investigated using response surface methodology. Extraction of cobalt and iron was more extensive than copper and silver, i.e., 35.7–96.2% Co and 72.6–100% Fe versus 8.50–35.4% Cu and 8.11–22.5% Ag. Statistical analysis of the experimental data has shown that increasing the acid concentration or temperature enhances the rate and extent of leaching of metals. Under suitable conditions, almost complete leaching of cobalt (99.9%), as well as high extractions of copper (95.9%) and silver (94.9%), were achieved. The activation energy, calculated to be 40.3 kJ/mol, indicates that nitric acid leaching of these metals occurs as a chemically controlled reaction. These findings have demonstrated that nitric acid as an effective oxidant/leaching agent could be suitably used for the extraction of cobalt, copper, and silver from scrap segments.

    • SDG 12 · Sorumlu Üretim ve Tüketim
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