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Koleksiyondaki öğeler
- MakaleAçık Erişim2016Scopus SJRQ2Assessing the effects of long-term recreational activities on landscape changes in Abant Natural Park, Turkey
Çakir, Günay; Müderrisoğlu, Haldun; Kaya, Latif Gürkan
Natural, protected areas offer many possibilities for recreation in rural areas such as camping, one of the most popular activities. The system established for protected areas in Turkey aims to provide a foundation for conserving areas for recreation. One such area, Abant Natural Park, is convenient for visits from Turkey’s two most populated metropolitan areas, Istanbul and Ankara. It also attracts tourists from other regions and countries. The aim of the present study was to evaluate the vegetation loss and land cover changes due to picnic/camping, transhumance, and construction over 40 years (1966–2004) in the park using data on visitor numbers, vegetation patches, corridors and connectivity. For evaluating landscape variables, remote sensing data and aerial photos were used. When aerial photos were imported into the ERDAS Imagine program, ground control points identified, and individual images orthorectified, land degradation was not found in the use of camping areas. Moreover, manmade areas (road, car park and hotel) observably increased, thus decreasing the forest lands. The findings show that the land use types that have had the greatest ecological impact are transhumance and construction of hotels, which also require infrastructure development. The intensity of the ecological effects mandates precautions to lessen the impacts and the need for continuing assessment to ensure sustainable use of the area.
AtıfScopus19WoS16OpenAlex19
İncele - BildiriYalnız künye2018Power spectrum analysis of EEG for watching 2D & 3D videos and resting state
Manshouri, Negin; Maleki, Masoud; Kayikcioglu, Temel
Analysis of the brain waves has become useful over than 80 years. Along with the medical application, the brain signal is also used for other research works in the last fifteen years. In this study, by considering the depth factor in the image of a video, the effects of it are checked on EEG. A video is displayed in two-dimensional (2D) and three-dimensional (3D) format to the subjects. After recording the EEG signals in video watching, the resting state was recorded. Three states are considered for a better understanding of these effects on EEG. These states involve 2D&3D, 2D&resting and 3D&resting. Frequency analysis of the signals is evaluated by two methods. These methods are Fast Fourier Transform (FFT) and Welch method.
AtıfScopus2WoS1OpenAlex3İncele - MakaleYalnız künye2017Scopus SJRQ2The operator method for local fractional linear differential equations
Ünal, Emrah; Gökdoğan, Ahmet; Cumhur, İshak
In this work, we give the particular solution for nonhomogeneous sequential linear conformable fractional differential equations with constant coefficients by using the operator method.
AtıfScopus9WoS7OpenAlex9İncele - MakaleYalnız künye2016Scopus SJRQ2Effect of plasma nitriding treatment on structural, tribological and electrochemical properties of commercially pure titanium
Çelik, Ilhan; Karakan, Mehmet
In this study, plasma nitriding treatment was applied to commercially pure titanium (Grade 2). Structural properties, electrochemical and tribological behaviours of the nitrided pure titanium specimens were comparatively investigated. Microstructure and morphology of the plasma nitrided specimens were analysed by X-ray diffraction and scanning electron microscopy. Furthermore, corrosion tests were conducted in Ringer's solution, which represents a human body environment, to determine electrochemical properties. Then, tribological and frictional properties were investigated using pin-on-disc tribometer, and a micro-hardness tester was used to measure the hardness of the coatings. The results showed that plasma nitrided specimens exhibited higher surface hardness than the untreated specimens did. In addition, the plasma nitrided specimens at 700 °C presented significantly better performance than the other plasma nitrided specimens (at 500 °C and 600 °C) under dry wear conditions. Moreover, corrosion test results showed that corrosion behaviours of untreated and nitrided samples had similar characteristic.
AtıfScopus9WoS6OpenAlex11
İncele - MakaleAçık Erişim2017Scopus SJRQ2Comparison of stochastic and random models for bacterial resistance
Merdan, Mehmet; Bekiryazici, Zafer; Kesemen, Tulay; Khaniyev, Tahir
In this study, a mathematical model of bacterial resistance considering the immune system response and antibiotic therapy is examined under random conditions. A random model consisting of random differential equations is obtained by using the existing deterministic model. Similarly, stochastic effect terms are added to the deterministic model to form a stochastic model consisting of stochastic differential equations. The results from the random and stochastic models are also compared with the results of the deterministic model to investigate the behavior of the model components under random conditions.
AtıfScopus25WoS25OpenAlex25İncele - MakaleYalnız künye2016Scopus SJRQ1Geochemical, fluid inclusion and isotopic (O, H and S) constraints on the origin of Pb-Zn±Au vein-type mineralizations in the Eastern Pontides Orogenic Belt (NE Turkey)
Akaryali, Enver
The mineralization area (Altinpinar, Torul-Gümüşhane) is situated in the Southern Zone of the Eastern Pontides Orogenic Belt (EPOB), which is one of the important metallogenic provinces in the Alpine-Himalayan belt and is intruded by the late Carboniferous granitic rocks (Gümüşhane Granitoid), an early to middle Jurassic volcano-sedimentary unit consisting mainly of basaltic-andesitic volcanic and pyroclastic rocks (Şenköy Formation) and Eocene basaltic-andesitic volcanic rocks (Alibaba Formation). The studied Pb-Zn ± Au mineralizations are related to silica veins ranging from a few millimeters to a maximum of 40. cm in thickness and are localized within fracture zones developed along the contact between the Gümüşhane Granitoid and Şenköy Formation. Silicic, sulfidic, hematitic, argillic, intense chloritic and carbonate alteration are the most common types from the fault lines toward the outer zones. Cavity filling and banded structures are widely observed. The mineral paragenesis comprises galena, sphalerite, pyrite, chalcopyrite, tennantite and quartz. Mineral chemistry studies indicate that ion exchange occurs between Zn and Fe in sphalerites, and the Zn/Cd ratio of sphalerites varies between 50.65 and 144.64. The homogenization temperatures measured from fluid inclusions vary between 170. °C and 380. °C, especially between 250. °C and 300. °C, and the wt.% NaCl eqv. salinity of ore-forming fluids is between 2.4 and 7.3 (4.7 on average), supporting an epithermal system in their origin. The values of sulfur isotopes, which are obtained from pyrite and galena minerals, range between - 8.3‰ and - 2.3‰, indicating that sulfur, which enables mineral formation, originates from magmatic genesis. The average formation temperature of the ore is 317. °C as determined with a sulfur isotope geothermometer. The values of oxygen and hydrogen isotopes vary between 8.5‰ and 10.2‰ and - 91‰ and -73‰, respectively. With regard to the compositions of oxygen and hydrogen isotopes, fluids comprising the mineralization are formed by the mixture of magmatic water and meteoric water. This situation is supported by the fact that the increase in the homogenization temperature indicates dilution with surface water but depends on the increase in the salinity of fluid inclusions. Considering all the data, it is clear that the studied mineralization is an epithermal vein-type mineralization that is related to granitic magmas.
AtıfScopus29WoS24OpenAlex32İncele - MakaleAçık Erişim2016Scopus SJRQ1Effect of piracetam and nimodipine on full-thickness skin burns in rabbits
Sari, Elif; Dincel, Gungor C.
The potential of several drugs for full-thickness skin burns has been investigated, but the treatment of such burns remains a challenge in plastic surgery. The present study was designed to determine the effect of systemic and topical administration of piracetam and nimodipine on full-thickness skin burn wound healing. A total of 36 New Zealand male rabbits were divided into six groups. Full-thickness skin burns were produced in all the groups, except the control group. Piracetam was administered systemically (piracetam-IV) and topically (piracetam-C) for 14 days, and nimodipine was administered systemically (nimodipine-IV) and topically (nimodipine-C) over the burn wounds for 14 days. The sham group underwent burn injury but was not administered any drug. After 21 days, gross examination and histopathological analysis were performed and the results were compared statistically. Nimodipine-C and nimodipine-IV had no effect on burn wound healing. However, both piracetam-IV and piracetam-C significantly enhanced the healing of the full-thickness skin burn wounds, although the latter was more effective, useful and practical in burn wound healing. The histopathological features of the wounds in the piracetam-C group were closer to those of the control group than those of the other groups. Piracetam-C rather than piracetam-IV may promote full-thickness burn wound healing in rabbits.
AtıfScopus2WoS2OpenAlex2İncele - MakaleYalnız künye2016Scopus SJRQ1Application of response surface methodology for optimizing the recovery of phenolic compounds from hazelnut skin using different extraction methods
Odabaş, Halil İbrahim; Koca, Ilkay
Hazelnut skin which is a rich source of phenolic compounds is a by-product of hazelnut roasting process. In present study, ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE) and supercritical carbon dioxide extraction (SCE) methods were applied for recovery of phenolic compounds from hazelnut skin. Response surface methodology was used to estimate optimum extraction conditions. Extraction studies were performed according to Box-Behnken Design. Temperature (UAE)/power (MAE), time and ethanol concentration were independent variables for UAE and MAE. The independent variables selected for SCE were temperature, time and pressure. The optimum extraction conditions were 45 min and 67.2–67.6% ethanol concentration, 600 W, 6 min and 55.03–56.23% ethanol concentration and 42.72–49.10 °C, 59.83–60.00 min and 10.01–11.48 bar, for UAE, MAE and SCE respectively. Total phenolic content, FRAP and 1/EC50 values at the optimum conditions were 122.99–123.01 mg GAE/g, 612.20–613.25 mmol Fe(II)/g and 4.36 mL/mg for UAE, 111.53–111.55 mg GAE/g, 582.44–582.52 mmol Fe(II)/g and 2.48 mL/mg for MAE and 69.59–72.64 mg GAE/g, 426.25–465.52 mmol Fe(II)/g and 2.18–2.27 mL/mg for SCE, respectively. Maceration was performed for comparison with novel methods. UAE was found to be the best method of the extraction of phenolic compounds from hazelnut skin with the highest total phenolic content and antioxidant activity values.
AtıfScopus89WoS78OpenAlex97İncele - MakaleYalnız künye2018Scopus SJRQ2Multipath interference cancelation in GPS time series under changing physical conditions by means of adaptive filtering
Üstün, Aydın; Yalvaç, Sefa
Multipath, a highly autocorrelated signal is observable phenomena during time periods longer than the sidereal period of Global Positioning System (GPS) satellites in their constellations. Multipath pattern and sidereal repeat time interaction are examined in terms of time series correlations of topocentric coordinates using GPS code and phase observations collected at high and low frequencies. The horizontal and vertical components at 5 and 30 s sampling rates are analyzed to detect and remove multipath classified by their MP1 levels and baseline lengths. For the selected 11 stations that have 24-hour data from CORS stations in the USA and Turkey, the repeat times of the GPS constellation were identified as a function of maximum cross-correlation of adjacent time series. The multipath interference signal from two-day time series data is removed by an adaptive filter to improve time series of coordinate estimates. After the filtering process, an effective epoch based position tracking has been accomplished, especially in the height component. The position errors disappeared to maximum possible extent in the pseudo-range measurements. Up to 70% improvement for the phase derived coordinates in reflective environment has been achieved over the baselines ranging from 1 km to 175 km. For the phase observables, the filter success directly related to the multipath level which is specific to the station.
AtıfScopus3WoS2OpenAlex4İncele - MakaleYalnız künye2018Scopus SJRQ3A novel hybrid approach for simplified neutrosophic decision-making with completely unknown weight information
Küçük, Gökçe Dilek; Şahin, Rıdvan
The simplified neutrosophic set (SNS) is a useful model to describe the indeterminacy information which widely exists in the real world. In this paper, we develop a multicriteria decision-making (MCDM) method under simplified neutrosophic environment in which the information about weights of criteria is completely unknown, and the decision criterion values take the form of simplified neutrosophic numbers (SNNs). In order to determine the weighting vector of the criteria, we establish an optimization model based on the basic ideal of the traditional gray relational analysis (GRA) method. By solving this model, we get a simple and exact formula which can be used to determine the criterion weights. Moreover, we utilize the dice similarity measure to determine the similarity measures between each alternative decision and the related ideal decisions. Then, based on the traditional GRA method and the technique for order preference by similarity to ideal solution (TOPSIS), some calculation steps are presented for solving a simplified neutrosophic multicriteria decision-making problem with completely unknown weight information. To avoid information loss, this model does not use the aggregation process of decision information. Comparisons of the suggested methodology with other methods are also made. Finally, a numerical example and an experimental analysis are proposed to illustrate the application of the proposed model.
AtıfScopus5WoS5OpenAlex6İncele - MakaleYalnız künye2018Scopus SJRQ2Determination of certain properties of scotch pine (Pinus sylvestris L.) wood which is impregnated with boron compounds and Quechua
Sen, Selim; Said Fidan, M.; Alkan, Elif; Sadiye Yaşar, S.
As the industrialisation and technological developments increase; the search for functional material which is environment-friendly, non-toxic, flame resistant, with a broad applicability and with high-temperature endurance also increases. Even though the wood material corresponds most of these features, its possession of an organic structure causes it to be affected negatively by damages occurring under proper conditions in the outdoor environment. Due to this reason, this study is conducted to prevent damages (biotic, abiotic pests, fire, etc.) caused by the environment to the wooden material, and to determine some physical and mechanical properties of wooden material impregnated with quechua, borax and boric acid, which are used to extend the usage life. Those features are needed in an outdoor environment. The Scotch pine (Pinus sylvestris L.) test specimens are prepared with borax, boric acid, borax+boric acid, from borax compounds, which have a great potential in Turkey, and with quechua, one of the natural impregnation substances. Then these samples are impregnated with three different (1%, 3%, 5%) solution concentrations according to ASTM 1413-76 standards and some physical-mechanical property changes are investigated. After impregnation, samples are tested and compared with control samples. According to the test results; the lowest oven dried density change is obtained in borax as 0.46 g . cm -3 in terms of boron compounds and the retention amount is determined to be highest with 3.83 kg.m -3 in the samples impregnated with boric acid. The bending strength and elastic modulus are found to be highest with 83.53 MPa and 10281 MPa in the samples impregnated with boric acid. When examined at the concentration level, it is determined to be highest with 81.89 MPa in samples with 3% concentration. There are statistical discrepancies with 55.77 MPa in the comprehensive strength parallel to grain in boric acid in terms of boron compounds.
AtıfScopus4WoS4İncele - Kitap BölümüYalnız künye2018Strategic communication management in Turkey
Taşdemir, Erdem; Aslan, Emre Ş.
- MakaleAçık Erişim2019Scopus SJRQ2Addressing the sneak-path problem in crossbar RRAM devices using memristor-based one Schottky diode-one resistor array
Gül, Fatih
Resistive random access memories (RRAMs) are favorable contenders in the race towards future technologies. Moreover, the desirable properties of memristor-based RRAM devices make them very good competitors in this field. The sneak paths problem poses one of the main difficulties in the construction of crossbar memory devices. This problem can be effectively suppressed by applying the 1diode-1resistor (1D1R) design structure. The Schottky diode has many advantages compared to the PN junction diode. The low-power (∼1 µW) ZnO active-layered thin-film (60 nm thick) one Schottky diode-one memristor device fabricated in this study included a top Ag electrode and a bottom Al electrode. The material makeup of the device was confirmed via energy dispersive X-ray spectroscopy (EDAX). The memristive and Schottky diode characteristics of the Ag/ZnO/Al device were resolved by measuring the time-dependent voltage/current. The characteristic pinched hysteresis memristive loops were observed at the first quadrant of the current-voltage plane, whereas the diode curves were seen at the third quadrant. Using the current-voltage curves, the height of the Schottky barrier, ideality factor and threshold voltage of the Schottky diode were found to be 0.68 eV, 3.75 and 0.49 V, respectively. After physical implementation and characterization of the one diode-one memristor device, its anti-crosstalk characteristics were investigated. Taking into account the 10% read margin, the maximum crossbar size was found to be 87.
AtıfScopus121WoS115OpenAlex127İncele - MakaleYalnız künye2019Scopus SJRQ2Natural convection in an enclosure with a pair of discrete heat sources
Saglam, Mehmet; Sarper, Bugra; Aydin, Orhan
An experimental and numerical study is carried out to investigate natural convection cooling characteristics of discrete heat sources in a rectangular enclosure. One of the sidewalls of the enclosure is heated by a pair of identical discrete heat sources, whereas the other sidewall is maintained at a constant temperature. The effect of the heat dissipation ratio of the heat sources on buoyancy-induced flow and heat transfer characteristics is investigated. Experimental studies are performed for a constant value of the modified Rayleigh number (Ra = 7.7 × 105) and three different values of the heat dissipation ratio (rh = q1 = q2 = 0.5, 1 and 2), whereas numerical studies cover the range of 104to 5 × 106 for the modified Rayleigh number and different values of the heat dissipation ratios between 0.25 and 2. In the experimental study, qualitative flow visualization studies are carried out as well as temperature measurements. In the numerical study, a commercial computational fluid dynamics code in ANSYS Fluent is used. The variations of the surface temperatures, the hot spot temperature, and the mean Nusselt number with the modified Rayleigh number and the heat dissipation ratio are obtained. Results are presented in terms of streamlines, isotherms, and heat lines.
AtıfScopus19WoS16OpenAlex26İncele - Kitap BölümüYalnız künye2018A study on rhetoric theory and rhetoric use in advertisement
Aslan, Emre Ş.; Demirel, Çağatay
- MakaleYalnız künye2018Scopus SJRQ4Determination of Late Embryonic Death Rates by Pregnancy Associated Glycoproteins and Rectal Examination in Cows
Paksoy, Zahid
In this study, it was aimed to make the pregnancy diagnosis with the determination of glycoproteins (PAG) associated pregnancy after insemination in the cows, and to determine the late embryonic mortality rates. As material, 2919 head cows in different races and ages were used in farms and family businesses in Kahramanmaraş province. Milk sample was taken on the 25–30 day after artificial insemination from cows. The level of PAG in these milk samples was analyzed by using the Milk Pregnancy Test Kit for cows. This kit was used according to the manufacturer's instructions. During the study, it was determined that 1660 cows were pregnant, 188 were suspicious and 1071 were not pregnant. The pregnant animals were examined by rectal palpation on the 50th day when their pregnancy was continued. Controls performed on the 50th day of pregnant cows showed that 1623 cows were still pregnant and 37 cows had late embryonic deaths. As a result, early pregnancies can be accurately detected by measuring the level of PAG in the cow's milk using the Milk Pregnancy Test Kit. It was concluded that late embryonic mortality rates could be detected and that this analysis could be used routinely.
- MakaleAçık Erişim2016Scopus SJRQ3Separation and preconcentration of Pb(II) and Cu(II) ions via carrier element-free coprecipitation using an acetohydrazide derivative
Tümay, Süreyya Oǧuz; Yazar, Murat; Ozdeş, Duygü; Bektaş, Hakan; Duran, Celal
A new method based on the combination of carrier element-free coprecipitation and flame atomic absorption spectrometric determination has been investigated for simultaneous separation and preconcentration of Pb(II) and Cu(II) ions in some environmental solid and liquid samples. The 2-f3-(4-methylbenzyl)-4-[2-(1H-indol-3-yl)ethyl]-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-ylg -N'-(phenylmethylene) acetohydrazide (MITA) was utilized as an organic coprecipitating agent without using a carrier element for coprecipitation of the analyte ions. The effects of experimental conditions including aqueous solution pH, MITA quantity, sample volume, standing time, and centrifugation rate and time were investigated in detail and optimized. The influences of some foreign ions were also evaluated on the quantitative recoveries of the analyte ions. The preconcentration factors were 125 for both analyte ions. The detection limits were 1.32 μgL-1 and 0.47 μg L-1 for Pb(II) and Cu(II) ions, respectively, and the relative standard deviations (RSDs) were lower than 4% for both analyte ions. After the accuracy of the method was checked, it was applied to sea and stream water as liquid samples and waste tea and tobacco as solid samples to determine the levels of Pb(II) and Cu(II) ions.
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İncele - MakaleYalnız künye2016Scopus SJRQ1Non-destructive testing of an ancient Masonry Bastion
Altunişik, Ahmet Can; Adanur, Süleyman; Genç, Ali Fuat; Günaydin, Murat; Okur, Fatih Yesevi
Historical masonry structures have seismic vulnerability and most damages and demolishes arise from the seismic actions like earthquakes. In this paper, the structural behavior of Zağanos Bastion is examined with experimental and numerical methods. The operational modal analysis technique is used to illustrate the dynamic characteristics of the bastion experimentally. Finite element model is developed by ANSYS software and dynamic characteristics of the bastion, such as natural frequencies and mode shapes are calculated numerically. Furthermore, time history seismic analysis is carried out. The results show that the ambient vibration measurements are enough to identify the structural response of the bastion. Maximum differences between the natural frequencies are attained as 26%. To minimize these differences, finite element model of the bastion should be updated by using some uncertain parameters. The principal stresses are satisfied in general, but the maximum tensile and compression stresses values exceed the allowable code limits at some points of the masonry components.
AtıfScopus29WoS30İncele - Kitap BölümüYalnız künye2018Human’s tragedy in the global world
Çıvgın, Ayşe Gül; Özsoy, Seda
- MakaleYalnız künye2016Scopus SJRQ1Determination of the effect of lead mine waste aggregate on some concrete properties and radiation shielding
Çullu, Mustafa; Ertaş, Haydar
The aim of this study is to determine the radiation absorption capacity of concretes produced from lead mine waste which cannot be processed economically as the lead content is low in the mines they are extracted. Lead mine waste (tallow) were exchanged at ratios of 25%, 50% and 75% respectively with barite and limestone aggregates and samples were prepared at C16, C25 and C35 classes. The compressive strength and the unit weight of the prepared samples were determined. The linear absorption coefficients of prepared concrete samples at 662 keV of energy were determined. In addition the relationship between the radiation absorption capacity and the compressive strength–unit weight was investigated. The experiments demonstrated that best absorption was in concrete samples with 100% barite content (100B). On the other hand in the concrete samples prepared from the mixture of limestone and lead mine waste aggregates, it was observed that radiation absorption capacity decreased due to decreasing amount of barite. In concrete samples prepared from the mixture of lead mine waste and limestone aggregates, it was observed that radiation absorption capacity increased due to increasing amount of mine waste aggregates in the concrete. As a result it was observed that lead mine waste aggregates do not absorb as much radiation as barite aggregates depending on the ratio increase of lead mine waste in the aggregate added to the concrete mixture. However the absorbed radiation amount was observed to be higher compared to limestone aggregates.
AtıfScopus77WoS70OpenAlex71İncele
