Onur, Tuğba Özge | Carlson, Johan E | Svanström, Erika | Hacıoğlu, Rıfat
Article | 2019 | Iranian Journal of Science and Technology - Transactions of Electrical Engineering43 ( 3 ) , pp.405 - 413
This paper demonstrates how flexural wave propagation in a thin plate can be modeled by estimating the combined effect of the excitation source signal and the impulse response of the ultrasonic sensor. The wave propagation in the plate is modeled using the wave equation for the flexural wave mode. A theoretical model for flexural wave propagation in thin plates has been derived, and it has been compared with measurements excited by tapping gently on the surface. The combined effects of the excitation source signal and the impulse response of the low-cost piezoelectric sensor are modeled using finite-impulse response and/or infinite- . . .impulse response filters. Thereafter, the performances of the selected filters are compared on estimating the wave propagation in a thin quartz glass plate. Results indicate that the most accurate estimation of wave propagation has been obtained using a linear phase filter which attributes all dispersions to the flexural wave. © 2018, Shiraz University Daha fazlası Daha az
Arca D. | Kutoğlu, Hakan Şenol | Becek K.
Article | 2018 | Environmental Monitoring and Assessment190 ( 12 ) , pp.405 - 413
Landslides are geomorphological phenomena that affect anthropogenic and natural features on the Earth’s surface. Many previous studies have identified several factors that have contributed to landslides. Among these factors are physical characteristics, such as slope, aspect, and land cover, of Earth’s surface. Moreover, landslides can be triggered by human activities such as underground mining. This study aims to identify landslide susceptibility areas by analyzing landslide-related factors, including land subsidence triggered by underground mining. The area of interest was Kozlu, Turkey, where underground mining has been in progre . . .ss for the past 100 years. Thus, to identify landslide risk zones, the multicriteria decision analysis method, together with the analytical hierarchy method, was used. The datasets included were topography, land cover, geological settings, and mining-induced land subsidence. The spatial extent of land subsidence was estimated using a previously published model. A landslide susceptibility map (LSM) was developed using a purposely developed GIS-based software. The results were compared with a terrain deformation map, which was developed in a separate study using the differential synthetic aperture radar interferometry (DInSAR) technique. The results showed a substantial correlation between the LSM and DInSAR map. Furthermore, it was found that ~ 88% of the very high and high landslide risk areas coincided with location of the past landslide events. These facts suggest that the algorithm and data sources used were sufficient to produce a sufficiently accurate LSM, which may be used for various purposes such as urban planning. © 2018, The Author(s) Daha fazlası Daha az
Özdoğan, Nizamettin | Kapukıran, Fatih | Öztürk Er, Elif | Bakırdere, Sezgin
Article | 2019 | Environmental Monitoring and Assessment191 ( 6 ) , pp.405 - 413
The emergence of magnetic materials has opened up doors to numerous applications including their use as sorbents for preconcentration of trace elements. Magnetic materials exhibit many unique advantages in sample preparation such as easy separation from the sample, high preconcentration factor, and short operation period. In the present study, magnetic cobalt material was synthesized, characterized, and used as an effective sorbent in a solid phase extraction process. Experimental variables of the extraction process including pH and volume of buffer solution, eluent concentration and volume, mixing type and period, and sorbent amoun . . .t were optimized to achieve maximum extraction efficiency. Instrumental variables of flame atomic absorption spectrophotometry and the type of slotted quartz tube were also investigated. Under the optimum conditions, the combined method provided a wide linear range between 50 and 200 ng/mL with detection and quantification limits of 15.4 ng/mL and 51.3 ng/mL, respectively. Relative standard deviations of the proposed method were less than 5.0% and a high enrichment factor of 86.7 was obtained. The proposed method was successfully applied to soil samples for the determination of trace tellurium. © 2019, Springer Nature Switzerland AG Daha fazlası Daha az
Özdoğan, Nizamettin | Kapukıran, Fatih | Mutluoğlu, Gülşen | Chormey, Dotse Selali | Bakırdere, Sezgin
Article | 2018 | Environmental Monitoring and Assessment190 ( 10 ) , pp.405 - 413
This study reports the optimization of a binary dispersive liquid-liquid microextraction method for the determination of iprodione, procymidone, and chlorflurenol by gas chromatography mass spectrometry. The study was aimed at using two extraction solvents to increase the extraction efficiency of all analytes. The binary solvents recorded results higher than the mono-solvents. After examining the effects of main experimental parameters and their interactions by analysis of variance, 200 µL of binary mixture (dichloromethane and 1,2-dichloroethane), 2.5 mL of ethanol, and 15 s vortex were obtained as optimum parameters. The detection . . . and quantification limits calculated for the analytes were found to be between 0.30–1.6 and 1.0–5.3 ng/mL, respectively. Enhancement in detection power calculated as a ratio of the binary extraction detection limit to the detection limit of direct GC-MS analysis was 105-, 214-, and 233-fold for chlorflurenol, iprodione, and procymidone, respectively. In order to check the accuracy of the developed method, recovery study was performed. Water sampled from a lake and two wastewater samples from treatment facilities were spiked at two concentrations, and the percent recovery calculated for the samples ranged between 87 and 116%. These results confirmed the suitability of the method to real samples for accurate determination of the analytes at trace levels. © 2018, Springer Nature Switzerland AG Daha fazlası Daha az
Alkan, Emel | Kapukıran, Fatih | Er Öztürk, Elif | Chormey, Dotse Selali | Keyf, Seyfullah | Özdoğan, Nizamettin | Bakırdere, Sezgin
Article | 2018 | Water, Air, and Soil Pollution229 ( 9 ) , pp.405 - 413
The potential risk of pesticides to cause harm to humans and other organisms even at trace levels calls for sensitive and accurate analytical techniques for their simultaneous qualitative and quantitative determinations. In this study, a sensitive binary dispersive liquid-liquid microextraction (B-DLLME) strategy was developed for the simultaneous determination of phorate and oxyfluorfen by gas chromatography mass spectrometry after extraction/preconcentration from aqueous solution. An experimental design was used to optimize parameters of the B-DLLME method to obtain maximum outcome. Under the optimum conditions of B-DLLME, the lim . . .it of detection (LOD) for phorate and oxyfluorfen were found to be 0.41 µg L-1 and 0.54 µg L-1, respectively. The detection limits correlate to about 37 and 73 folds enhancement in detection powers when compared to direct GC-MS determination of phorate and oxyfluorfen, respectively. In order to find out the applicability of developed method to real samples, recovery tests were performed for 20 µg L-1 of phorate and oxyfluorfen spiked in well water samples. Percent recovery values were found to be 94.5% for phorate and 101.9% for oxyfluorfen. © 2018, Springer Nature Switzerland AG Daha fazlası Daha az
Onur Y.A. | İmrak C.E. | Onur T.Ö.
Article | 2017 | Experimental Techniques41 ( 5 ) , pp.475 - 482
Investigation on theoretical and experimental determination of bending over sheave fatigue lifetimes of rotation resistant steel wire ropes has been conducted. Effects of sheave size and tensile load on bending over sheave fatigue lifetimes of investigated rope have been presented. Bending over sheave fatigue life prediction according to effects of tensile load and sheave diameter has been presented by using artificial neural networks. The results point out that constructed ANN model estimations and experimental results have powerful correlation. © 2017, The Society for Experimental Mechanics, Inc.
Book Part | 2016 | Musculoskeletal Research and Basic Science , pp.51 - 59
In this chapter, essentials of finite element analysis on musculoskeletal biomechanics are studied. For this reason, some fundamental types of finite elements, methodology, and difficulties of finite element analysis are considered. Also, some information on well-known general purpose finite element codes preferred in biomechanics and biomaterials world is given. Before discussing orthopedic researches for clinical relevance, an example of two-dimensional finite element analysis is examined. © Springer International Publishing Switzerland 2016.
Akyol S. | Ben Nissan B. | Karacan I. | Yetmez M. | Gokce H. | Suggett D.J. | Oktar F.N.
Article | 2019 | Journal of the Australian Ceramic Society55 ( 3 ) , pp.893 - 901
The aim of this study is to obtain pure natural hydroxyapatite (HAp) and tricalcium phosphate (TCP) from a Goniopora spp. and from hump coral (Porites cylindrica), both sourced from Australia. Due to the nature of the conversion process, commercial coralline HAp has retained coral or CaCO3, and the structure possesses both nano- and mesopores within the interpore trabeculae resulting in high dissolution rates. To overcome these limitations, a newly patented coral double-conversion technique has been developed. The current technique involves a two-stage application route where in the first-stage complete conversion of coral to pure H . . .Ap is achieved. In the second stage, a sol-gel-derived HAp nanocoating is directly applied to cover the meso- and nanopores within the intrapore material, while maintaining the large pores. Here, we specifically investigated the morphological changes and characterized these corals prior to and after conversion. For this purpose, four groups designated as C0, C1, C2, and C3 were used. C0 is Porites, Goniopora, and cylindrica; the original coral is calcium carbonate with aragonite structure that contains proteins and polysaccharides. C1 is coral cleaned under ultrasound in bleach diluted with water. C2 is coral converted to hydroxyapatite (HAp) by hydrothermal treatment method at 200 °C under pressure in the presence of ammonium biphosphate. C3 is obtained by coating C2 with sol-gel alkoxide-derived nanohydroxyapatite to obtain a more bioactive osteoconductive material and improve mechanical properties. All groups were characterized by XRD, EDAX, DTA/TGA, and SEM. The results showed that the biaxial strengths of the C2 and C3 were significantly higher than the original coral. The work also showed the advantages of the hydrothermal conversion method and the effect of the nanocoating which is expected to improve the final bioactivity through microstructural changes of the surfaces. © 2019, Australian Ceramic Society Daha fazlası Daha az
Article | 2018 | Eurasian Economic Review , pp.893 - 901
This study examines the relationship between price support, valuation and returns in a unique sample of 114 firms going public at Borsa Istanbul. I utilize disclosed information in pre-issue prospectuses and valuation reports as well as post-issue material event files to document that: initial public offerings implementing price support have lower initial and short-term returns, and larger optimistic valuation bias relative to offerings without price support. Tests show that underwriters’ valuation bias increases the probability of implementing price support, and one standard deviation increase in price support is associated with a . . .19.4% decline in short-term returns, after controlling for the selection bias associated with simultaneously deciding the offer price and price support. © 2018, Eurasia Business and Economics Society Daha fazlası Daha az
Zadbagher E. | Becek K. | Berberoglu S.
Article | 2018 | Environmental Monitoring and Assessment190 ( 8 ) , pp.893 - 901
Land use and land cover (LULC) changes affect several natural environmental factors, including soil erosion, hydrological balance, biodiversity, and the climate, which ultimately impact societal well-being. Therefore, LULC changes are an important aspect of land management. One method used to analyze LULC changes is the mathematical modeling approach. In this study, Cellular Automata and Markov Chain (CA-MC) models were used to predict the LULC changes in the Seyhan Basin in Turkey that are likely to occur by 2036. Satellite multispectral imagery acquired in the years 1995, 2006, and 2016 were classified using the object-based class . . .ification method and used as the input data for the CA-MC model. Subsequently, the post-classification comparison technique was used to determine the parameters of the model to be simulated. The Markov Chain analyses and the multi-criteria evaluation (MCE) method were used to produce a transition probability matrix and land suitability maps, respectively. The model was validated using the Kappa index, which reached an overall level of 77%. Finally, the LULC changes were mapped for the year 2036 based on transition rules and a transition area matrix. The LULC prediction for the year 2036 showed a 50% increase in the built-up area class and a 7% decrease in the open spaces class compared to the LULC status of the reference year 2016. About an 8% increase in agricultural land is also likely to occur in 2036. About a 4% increase in shrub land and a 5% decrease in forest areas are also predicted. © 2018, Springer Nature Switzerland AG Daha fazlası Daha az
Article | 2019 | Iranian Journal of Science and Technology, Transaction A: Science43 ( 2 ) , pp.639 - 643
In this work, the X-PMSP program, a new user-friendly code for calculating the mass stopping power of elements for charged particles, is introduced with a few sample calculations for each charged particle. The mass stopping power calculations of X-PMSP program are compared with the other mass stopping power results in the literature. These results show that X-PMSP program calculations of mass stopping power for charged particles on elements are suitable. X-PMSP program also contributes to the literature, especially, in radioisotope production, because in addition to proton and alpha charged particles, the mass stopping power of He-3 . . ., deuteron, and triton charged particles can be calculated for 98 elements (Z < 98). © 2018, Shiraz University Daha fazlası Daha az
Sekertekin A. | Kutoglu S.H. | Kaya S.
Article | 2016 | Environmental Monitoring and Assessment188 ( 1 ) , pp.1 - 15
The aim of this study is to analyze spatio-temporal variability in Land Surface Temperature (LST) in and around the city of Zonguldak as a result of the growing urbanization and industrialization during the last decade. Three Landsat 5 data and one Landsat 8 data acquired on different dates were exploited in acquiring LST maps utilizing mono-window algorithm. The outcomes obtained from this study indicate that there exists a significant temperature rise in the region for the time period between 1986 and 2015. Some cross sections were selected in order to examine the relationship between the land use and LST changes in more detail. T . . .he mean LST difference between 1986 and 2015 in ERDEMIR iron and steel plant (6.8 °C), forestland (3 °C), city and town centers (4.2 °C), municipal rubbish tip (-3.9 °C), coal dump site (12.2 °C), and power plants’ region (7 °C) were presented. In addition, the results indicated that the mean LST difference between forestland and city centers was approximately 5 °C, and the difference between forestland and industrial enterprises was almost 8 °C for all years. Spatio-temporal variability in LST in Zonguldak was examined in that study and due to the increase in LST, policy makers and urban planners should consider LST and urban heat island parameters for sustainable development. © 2015, Springer International Publishing Switzerland Daha fazlası Daha az