Mühendislik ve Doğa Bilimleri Fakültesi Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.13091/1624

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Citation - WoS: 9
Citation - Scopus: 11
Adrenal Tumor Segmentation Method for Mr Images
(ELSEVIER IRELAND LTD, 2018) Barstuğan, Mücahid; Ceylan, Rahime; Asoğlu, Semih; Cebeci, Hakan; Koplay, Mustafa
Background and objective: Adrenal tumors, which occur on adrenal glands, are incidentally determined. The liver, spleen, spinal cord, and kidney surround the adrenal glands. Therefore, tumors on the adrenal glands can be adherent to other organs. This is a problem in adrenal tumor segmentation. In addition, low contrast, non-standardized shape and size, homogeneity, and heterogeneity of the tumors are considered as problems in segmentation. Methods: This study proposes a computer-aided diagnosis (CAD) system to segment adrenal tumors by eliminating the above problems. The proposed hybrid method incorporates many image processing methods, which include active contour, adaptive thresholding, contrast limited adaptive histogram equalization (CLAHE), image erosion, and region growing. Results: The performance of the proposed method was assessed on 113 Magnetic Resonance (MR) images using seven metrics: sensitivity, specificity, accuracy, precision, Dice Coefficient, Jaccard Rate, and structural similarity index (SSIM). The proposed method eliminates some of the discussed problems with success rates of 74.84%, 99.99%, 99.84%, 93.49%, 82.09%, 71.24%, 99.48% for the metrics, respectively. Conclusions: This study presents a new method for adrenal tumor segmentation, and avoids some of the problems preventing accurate segmentation, especially for cyst-based tumors. (C) 2018 Elsevier B.V. All rights reserved.
Citation - WoS: 50
Citation - Scopus: 55
Advanced Oxidation of Landfill Leachate: Removal of Micropollutants and Identification of By-Products
(ELSEVIER, 2021) Ateş, Havva; Argun, Mehmet Emin
Landfill leachate contains several macropollutants and micropollutants that cannot be removed efficiently by conventional treatment processes. Therefore, an advanced oxidation process is a promising step in post or pre-treatment of leachate. In this study, the effects of Fenton and ozone oxidation on the removal of 16 emerging micropollutants including polycyclic aromatic hydrocarbons (PAHs), phthalates, alkylphenols and pesticides were investigated. The Fenton and ozone oxidation of the leachate were performed with four (reaction time: 20-90 min, Fe(II) dose: 0.51-2.55 g/L, H2O2 dose: 5.1-25.5 g/L and pH: 3-5) and two (ozonation time: 10-130 min and pH: 4-10) independent variables, respectively. Among these operating conditions, reaction time played more significant role (p-value < 0.05) in eliminating di-(2-Ethylhexyl) phthalate, 4-nonylphenol and 4-tert-octylphenol for both processes. The results showed that Fenton and ozone oxidation processes had a high degradation potential for micropollutants except for the PAHs including four and more rings. Removal efficiencies of micropollutants by ozone and Fenton oxidation were determined in the range of 5-100%. Although the removal efficiencies of chemical oxygen demand (COD) and some micropollutants such as phthalates were found much higher in the Fenton process than ozonation, the degradation products occurred during the Fenton oxidation were a higher molecular weight. Moreover, the oxidation intermediates for the both processes were found as mainly benzaldehyde, pentanoic acid and hydro cinnamic acid as well as derivatives of naphthalenone and naphthalenediol. Also, acid ester with higher molecular weight, naphthalene-based and phenolic compounds were detected in the Fenton oxidation.
Citation - WoS: 8
Citation - Scopus: 12
The Aerodynamic Effects of Blade Pitch Angle on Small Horizontal Axis Wind Turbines
(Emerald Group Publishing Ltd, 2022) Kaya, Mehmet Numan; Uzol, Oguz; Ingham, Derek; Köse, Faruk; Büyükzeren, Rıza
Purpose The purpose of this paper is to thoroughly investigate the aerodynamic effects of blade pitch angle on small scaled horizontal axis wind turbines (HAWTs) using computational fluid dynamics (CFD) method to find out the sophisticated effects on the flow phenomena and power performance. Design/methodology/approach A small HAWT is used as a reference to validate the model and examine the aerodynamic effects. The blade pitch angle was varied between +2 and -6 degrees, angles which are critical for the reference wind turbine in terms of performance, and the CFD simulations were performed at different tip speed ratio values, lambda = 2, 3, 4, 5, 6, 7, 9 and 10.5 to cover the effects in various conditions. Results are examined in two different aspects, namely, general performance and the flow physics. Findings The power performance varies significantly according to the tip speed ratio; the power coefficient increases up to a certain pitch angle at the design tip speed ratio (lambda = 6); however, between lambda = 2 and 4, the more the blade is pitched downwards, the larger is the power coefficient, the smaller is the thrust coefficient. Similarly, for tip speed ratios higher than lambda = 8, the positive effect of the low pitch angles on the power coefficient at lambda = 6 reverses. The flow separation location moves close to the leading edge at low tip speed ratios when the blade is pitched upwards and the also tip vortices become more intense. In conclusion, the pitch control can significantly contribute to the performance of small HAWTs depending on different conditions. Originality/value In the literature, only very little attention has been paid to the aerodynamic effects of pitch angle on HAWTs, and no such study is available about the effects on small HAWTs. The change of blade pitch angle was maintained at only one degree each time to capture even the smallest aerodynamic effects, and the results are presented in terms of the power performance and flow physics.
Citation - WoS: 14
Citation - Scopus: 14
All-Dry Synthesis of Poly(2-Ethylhexyl Acrylate) Nanocoatings Using Initiated Chemical Vapor Deposition Method
(ELSEVIER SCIENCE SA, 2019) Şakalak, Hüseyin; Karaman, Mustafa
In this study, Poly(2-ethylhexyl acrylate) (PEHA) thin films were deposited on different substrates by initiated chemical vapor deposition (iCVD) technique. Being a long alkyl chain acrylate with a suitably low glass transition temperature, PEHA is an important member of acrylates family, which is used extensively in adhesives, paints, and coating applications. In iCVD, use of the tert-butyl peroxide as an initiator allowed a deposition rate of 155 nm/min at a filament temperature of 280 degrees C. Precursor flow ratios, filament and substrate temperatures were found to be important parameters that effect the deposition rates. The negative relation between substrate temperature and deposition rates implied an adsorption limited kinetics. FTIR and XPS analyses of the deposited films confirmed that the chemical functionality of the EHA monomer preserved well after iCVD. It was also revealed that the as-deposited films are smooth, uniform and optically transparent. PEHA film deposited by iCVD on glass improved the optical transmittance of glass, by acting as an anti-reflection coating due to its suitable refractive index of 1.45.
Citation - WoS: 17
Citation - Scopus: 19
Analysis of Electrospinning and Additive Effect on ? Phase Content of Electrospun Pvdf Nanofiber Mats for Piezoelectric Energy Harvester Nanogenerators
(Institute of Physics, 2022) Oflaz, Kamil; Özaytekin, İlkay
Harvesting energy with piezoelectric nanoparticles enables the development of self-powered devices. Poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF) has been widely used in a variety of fields due to its superior piezoelectric properties. PVDF’s piezoelectric performance is affected by the presence of polar phase in the crystalline structure. The electrospinning process was used in this study to achieve high ? phase ratios in the PVDF crystalline structure using various additives (graphene, boron nitride, and quartz (SiO2)). The Taguchi experimental design method was used to determine the most significant parameters affecting ? phase content from seven factors, as well as the optimal levels of the significant factors. The Fourier transform infrared, x-ray diffraction, scanning electron microscopy, energy-dispersive x-ray and differential scanning calorimetry analyses were used to characterize the composite PVDF nanofiber mats produced under optimal conditions, and the output voltage was measured using an oscilloscope. The composite PVDF nanofiber mat with the highest ? phase concentration demonstrated a maximum output voltage of 8.68 V under optimal conditions, indicating that it outperformed than pure PVDF under equal electrospinning conditions. © 2022 IOP Publishing Ltd.
Citation - WoS: 37
Citation - Scopus: 46
Analysis of the Cp Structure of the Yukawa Coupling Between the Higgs Boson and Tau Leptons in Proton-Proton Collisions at Root S=13 Tev
(Springer, 2022) Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Chatterjee, S.; Dragicevic, M.; Güler, Yalçın; The CMS Collaboration
The first measurement of the CP structure of the Yukawa coupling between the Higgs boson and tau leptons is presented. The measurement is based on data collected in proton-proton collisions at root s = 13 TeV by the CMS detector at the LHC, corresponding to an integrated luminosity of 137 fb(-1). The analysis uses the angular correlation between the decay planes of tau leptons produced in Higgs boson decays. The effective mixing angle between CP-even and CP-odd tau Yukawa couplings is found to be -1 +/- 19 degrees, compared to an expected value of 0 +/- 21 degrees at the 68.3% confidence level. The data disfavour the pure CP-odd scenario at 3.0 standard deviations. The results are compatible with predictions for the standard model Higgs boson.
Citation - WoS: 18
Citation - Scopus: 19
Antibacterial Activity of Linezolid Against Gram-Negative Bacteria: Utilization of Epsilon-Poly Capped Silica Xerogel as an Activating Carrier
(MDPI, 2020) Kaya Güzel, Gülcihan; Medaglia, Serena; Candela-Noguera, Vicente; Tormo-Mas, Maria Angeles; Marcos, Maria Dolores; Aznar, Elena; Martinez-Manez, Ramon
In recent times, many approaches have been developed against drug resistant Gram-negative bacteria. However, low-cost high effective materials which could broaden the spectrum of antibiotics are still needed. In this study, enhancement of linezolid spectrum, normally active against Gram-positive bacteria, was aimed for Gram-negative bacteria growth inhibition. For this purpose, a silica xerogel prepared from a low-cost precursor is used as a drug carrier owing to the advantages of its mesoporous structure, suitable pore and particle size and ultralow density. The silica xerogel is loaded with linezolid and capped with epsilon-poly-l-lysine. The developed nano-formulation shows a marked antibacterial activity against to Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. In comparison to free linezolid and epsilon-poly-l-lysine, the material demonstrates a synergistic effect on killing for the three tested bacteria. The results show that silica xerogels can be used as a potential drug carrier and activity enhancer. This strategy could provide the improvement of antibacterial activity spectrum of antibacterial agents like linezolid and could represent a powerful alternative to overcome antibiotic resistance in a near future.
Citation - WoS: 42
Citation - Scopus: 46
Apricot Kernel Shell Waste Treated With Phosphoric Acid Used as a Green, Metal-Free Catalyst for Hydrogen Generation From Hydrolysis of Sodium Borohydride
(PERGAMON-ELSEVIER SCIENCE LTD, 2020) Fangaj, Enis; Ceyhan, Ayhan Abdullah
In this study, grinded apricot kernel shell (GAKS) biobased waste was used for the first time as a cost-effective, efficient, green and metal-free catalyst for hydrogen generation from the hydrolysis reaction of sodium borohydride (NaBH4). For the hydrogen production by NaBH4 hydrolysis reaction, GAKS was treated with various acids (HCl, HNO3, CH3COOH, H3PO4), salt (ZnCl2) and base (KOH). As a result, the phosphoric acid (H3PO4) demonstrated better catalytic activity than other chemical agents. The hydrolysis of NaBH4 with the GAKS-catalyst (GAKS(cat)) was studied depending on different parameters such as acid concentration, furnace burning temperature and time, catalyst amount, NaBH4 concentration and hydrolysis reaction temperature. The obtained GAKS(cat) was characterized by ICP-MS, elemental analysis, TGA, XRD, FT-IR, Boehm, TEM and SEM analyses and was evaluated for its catalytic activity in the hydrogen production from the hydrolysis reaction of NaBH4. According to the results, the optimal H3PO4 percentage was found as 15%. The maximum hydrogen generation rate from the hydrolysis of NaBH4 with the GAKS(cat) was calculated as 20,199 mL min(-1) g(cat)(-1) As a result, it can be said that GAKS treated with 15% H3PO4 as a catalyst for hydrogen production is an effective alternative due to its high hydrogen production rate. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Citation - WoS: 72
Citation - Scopus: 78
Article Info Keywords: Cfrp Reinforced Concrete T-Beams Strengthening Analytical Analysis Anchorage Building Codes Damage Analysis
(Elsevier Science Inc, 2022) Yazman, Şakir; Aksoylu, Ceyhun; Gemi, Lokman; Arslan, Musa Hakan; Hamad, Ahmed Abed; Özkılıç, Yasin Onuralp
Strengthening of shear deficient T-beams is not as easy as rectangular beams due to the presence of slabs. In this study, externally bonded reinforcement (EBR) such type of reinforced concrete shear deficient T-beams with and without anchorage in different CFRP configurations was experimentally and analytically investigated. Pursuant to this goal, nine half-scale T-beams were produced and tested with monotonic loading under four points. Seven of these T-beams are strengthened with partial CFRP strip and one is strengthened with full CFRP wrapped in the shear span. The failures of strengthened beams are initiated with the debonding failure of FRP sheets followed by brittle shear failure. In order to prevent this failure, two specimens with partial CFRP strip are fixed to the beam by using anchors at different angles of 45 and 90. The experimental results indicated that the contribution of EBR to the shear capacity is significant and depends on different variables such as anchorage angle, strengthening type. Moreover, the strengthening method that gives the most effective results in strengthening T-beams are full wrapping CFRP and partial CFRP with a 45-degree anchorage type. The anchorage application increased the shear capacity by 42.6%-53.8% compared to the reference specimens. In addition, the anchors with angle of 45 increased stiffness by 37%. In terms of ductility, the best result was given by the type of strengthening where the slabs were broken and the beam was completely wrapped. This method contributed 42%-80% more to ductility than other methods. The obtained experimental results were also compared with the empirical correlations given by ACI 440.2R-17, TBEC-2019 and FIB-2010 and recommendations are given. Especially in fully wrapped beams, the estimation of ACI was determined to be 96%. The estimations of the other codes are far from meeting the experimental results; therefore, essential improvements should be applied to the codes, especially with regard to CFRP deformation and approaches for anchored connections.
Citation - WoS: 13
Citation - Scopus: 14
Assessing the Performance of Bds-3 for Multi-Gnss Static and Kinematic Ppp-Ar
(Elsevier Ltd, 2022) Öğütçu, S.; Alcay, S.; Özdemir, Behlül Numan; Li, P.; Zhang, Y.; Konukseven, C.; Atiz, O.F.
As of 2021, a total of four different GNSS constellations – namely, GPS, GLONASS, Galileo, and BDS-3 – can be used with Full Operational Capability (FOC). In this work, the contribution of BDS-3 FOC to GPS + GLONASS + Galileo (GRE) PPP-AR is investigated, considering the three different cut-off angles (7°, 30°, and 45°) and different lengths of static observation sessions (24-, 12-, 6-, 3-, 1-, 0.5-, 0.25-hour). The data of 31 IGS-MGEX stations is processed with GRE PPP-AR and GREC3 (GPS + GLONASS (using float mode) + Galileo + BDS-3) PPP-AR modes. The results showed that BDS-3 degraded the horizontal (except for 24-h sessions) and vertical accuracy of static GRE PPP-AR solutions regardless of the elevation cutoff angle and observation time. The kinematic results showed that BDS-3 significantly contributed to the accuracy of GRE kinematic PPP-AR for 30° and 45° cutoff angles. The convergence time analysis showed that BDS-3 only contributes to GRE kinematic PPP-AR for the vertical component. © 2022 COSPAR
Citation - WoS: 14
Citation - Scopus: 15
Assessing the Structural Behavior of Reinforced Concrete Beams Produced With Macro Synthetic Fiber Reinforced Self-Compacting Concrete
(Elsevier Science Inc, 2022) Ünal, Alptuğ; Uğur, Ahmet Emin
This study was carried out to investigate the effect of polypropylene-based structural macro synthetic fiber (PPF) reinforcement on the behavior of reinforced concrete beams produced with self-compacting concrete (SCC). For this purpose, it was aimed to spread the PPFs homogeneously in the concrete by making use of the fluid form of SCC. The variation of non-fibrous-low-medium-high PPF ratios and stirrup ratios in specimens produced with SCC are the variables of the study. In this study, the shear span/effective depth ratio (a/d) was taken as the limit value of 2.5 in terms of shear and bending, and the behavior of reinforced concrete beams at this critical value was investigated. Within the scope of the study, 16 large-scale specimens were tested under monotonic loads in a 4-point bending setup. Load-displacement, stiffness and energy consumption graphs of the tested specimens were drawn, ductility values were determined, crack distributions were examined and failure modes were determined. The graphs and the determined values were interpreted in detail. In addition, numerical models of the tested specimens were created and analyzed using a finite element program. Experimental study results were compatible with numerical analysis results and similar results were obtained. According to the results obtained, it was observed that the specimens produced with SCC and using PPF reinforcements at appropriate ratios (5 kg/ m3 and 10 kg/m3) exhibited bending failure even if stirrups were not used.
Citation - WoS: 26
Citation - Scopus: 25
An Assessment of Deterioration in Cultural Heritage: the Unique Case of Eflatunpinar Hittite Water Monument in Konya, Turkey
(SPRINGER HEIDELBERG, 2020) Bozdağ, Ali; İnce, İsmail; Bozdağ, Ayla; Hatır, M. Ergün; Tosunlar, M. Bahadır; Korkanç, Mustafa
Stone monuments are important symbols of cultural heritage of countries. However, many environmental factors negatively affect these monuments. The increasing damage on the stone monuments and the danger of irreversible loss of cultural heritage have resulted in growing efforts for the preservation of the monuments. Eflatunpinar Hittite Water Monument in Beysehir, Konya, Turkey, is a unique Hittite cultural monument that has survived for nearly 3200 years even though it has been exposed to many environmental effects. In this study, non-destructive testing (NDT) was used to detect the degradation on the building stones of the Eflatunpinar Hittite Water Monument and change-deterioration maps were prepared subsequently. It was also investigated whether the chemistry of the Eflatunpinar spring water may cause deterioration. Additionally, the petrographic, chemical, and physico-mechanical properties of the rocks taken from the ancient stone quarry were determined in order to compare with the properties of the monument's building stones. Based on the physico-chemical characteristics of the Eflatunpinar spring water and XRD results of crusts in building stone surface of the monument, it was identified that water can be effective on the formation of calcite and gypsum crusts especially in the lower parts of the monument. However, applied NDT methods and change-deterioration maps indicated that the deterioration as well as neglect and abandonment in the monument are mostly associated with the capillary effect of the flowing water through the structure and the deterioration effect is more apparent in contact points between the building stone and the flowing water. Additionally, in the building stones above the capillary front, the conservation condition is significantly better.
Citation - WoS: 9
Citation - Scopus: 8
Atmospheric and Anthropogenic Deterioration of the Ivriz Rock Monument: Eregli-Konya, Central Anatolia, Turkey
(SPRINGER HEIDELBERG, 2021) Korkanç, Mustafa; İnce, İsmail; Hatır, Mehmet Ergün; Tosunlar, Mehmet Bahadır
The aim of this study is to determine the extent of deterioration of the limestone on which the Ivriz rock monument is engraved. This monument is near Aydinkent (Ivriz) village and located 12 km from the Eregli district of Konya. The height of the Ivriz Hittite monument is 4.20 m and its width is 2.40 m. It dates back to the second-half of the eighth century BC. The rocks on which the reliefs are engraved are limestone; the lower parts are brecciated with open cracks, and the upper parts show fewer cracks with smaller gaps. To enable the identification of the characteristics of the rocks on which the figures are located, non-destructive methods were used. Surface humidity, P wave velocity, thermal imaging, and Schmidt hardness measurement were applied to the wall surface of the monument, and mapping studies were conducted. Surface humidity varied between 26 and 58% with the highest values measured in the sections where the cracks are densest. The P wave velocity measured at the rock monument varied between 1.6 and 5.8 km/s, with the lowest values found in the sections where cracks were denser. Schmidt rebound values varied between 18 and 42, with higher values obtained in those sections with fewer effects of deterioration. According to the detailed observations and data obtained from non-destructive techniques (NDT) and laboratory data, the most significant deterioration has resulted from atmospheric conditions and damage by humans. The most common effects of degradation in this area are erosion by water, granular disintegration, cracks, microkarst, black crust, biodegradation (lichen, algae, and higher plants), and vandalism.
Citation - WoS: 70
Citation - Scopus: 75
Behavior of Cfrp-Strengthened Rc Beams With Circular Web Openings in Shear Zones: Numerical Study
(Elsevier Science Inc, 2022) Özkılıç, Yasin Onuralp; Aksoylu, Ceyhun; Yazman, Şakir; Gemi, Lokman; Arslan, Musa Hakan
In practice, especially the basement floor beams are drilled and damaged by the users. In some cases, this damage to the beams can be significant for the load-bearing element and the whole structure. In this study, the behavior of reinforced concrete beams with circular openings and the failure types resulting from strengthening these beams with CFRP are parametrically investigated. The diameter of the opening/beam height ratio (D/H), con-crete compressive strength, stirrup spacing, the position of the opening to the beam support, the type of CFRP application, CFRP ply orientation, and the number of CFRP layers were selected as parameters. Numerical models were verified using 9 specimens having different circular openings with/without CFRP strengthening and the analyses of 95 numerical models with the selected parameters were carried out utilizing the finite element program, ABAQUS. The ultimate load capacity, ductility, stiffness, energy dissipation capacity and failure modes of the beams were determined. As a result of the study, it was observed that there was no significant loss in ductility for the beams with D/H < 0.3 and the number of CFRP layer and type of application did not have a significant effect on D/H < 0.44. However, for the beams with D/H > 0.64, the CFRP application that completely surrounds openings should be preferred instead of partial CFRP strengthening. In addition, the concrete strength is an effective parameter for the beams with D/H < 0.44. The effect of the stirrup spacings in the beam on the ductile behavior was also limited with the increase in the hole diameter. The number of CFRP layers should theoretically be 4 for an effective strengthening in beams with D/H > 0.44. Finally, U wrapping is recommended instead of using full wrapping. It has been seen that the location and diameter of the hole are very important parameters in the failure type of the beam.
Citation - WoS: 37
Citation - Scopus: 47
Behaviour of Waste Polypropylene Pyrolysis Char-Based Epoxy Composite Materials
(SPRINGER HEIDELBERG, 2020) Soğancıoğlu, Merve; Yel, Esra; Ahmetli, Gülnare
In this study, polypropylene (PP) plastic wastes were pyrolysed. Solid pyrolysis product (char) was used as filler material for the preparation of epoxy composite. 300, 400, 500, 600 and 700 degrees C were selected as final pyrolysis temperatures. Solid pyrolysis product (char) was analysed by elemental, FTIR, SEM, BET and TGA analysis. The epoxy composite samples were prepared with char obtained from pyrolysis. Mechanical properties of composites were analysed by hardness, tensile strength, elongation at break, electrical conductivity tests to explain the effects of pyrolysis temperature and char doses over composite properties. Thermogravimetric properties of composites were determined by TGA analyses. The water absorption behaviour of composite samples was determined by water adsorption test. Epoxy composite produced from PP char obtained under 300 degrees C showed the most ideal behaviour.
Citation - WoS: 42
Citation - Scopus: 49
Bi-Objective Coordinated Production and Transportation Scheduling Problem With Sustainability: Formulation and Solution Approaches
(Taylor & Francis Ltd, 2023) Yağmur, Ece; Kesen, Saadettin Erhan
This paper studies a new variant of integrated production scheduling and vehicle routing problem where production of customer orders are performed under job-shop environment and order deliveries are made by a heterogeneous fleet of vehicles, each of which is allowed to take multiple trips. Two conflicting objectives are considered, namely minimisation of the total amount of CO2 emitted by the vehicles and minimisation of maximum tardiness resulting from late deliveries. To this end, we present a bi-objective mixed-integer programming formulation. Augmented epsilon-Constraint (Augmecon) method is implemented to find Pareto optimal solutions. Due to problem complexity, Augmecon cannot provide solutions even with small-sized problems. Thus, we adopt Pareto Local Search (PLS) and non-dominated sorting genetic algorithm-II (NSGA-II) for practical sized instances. For small-sized instances involving 5, 6, and 7 customers, experimental results indicate that CPU time of Augmecon are 11, 84, and 524 sec, respectively with an average number of Pareto efficient solution of 3.5. In terms of hypervolume index, Augmecon shows the best performance, followed by NSGA-II with 11.32% and PLS with 20.75% degradation for small-sized instances. For medium and large-sized instances, PLS shows worse performance than NSGA-II by 16.87% and 40.48%.
Citation - WoS: 50
Citation - Scopus: 55
Buildings Damages After Elazig, Turkey Earthquake on January 24, 2020
(SPRINGER, 2021) Doğan, Gamze; Ecemiş, Ali Serdar; Korkmaz, Serra Zerrin; Arslan, Musa Hakan; Korkmaz, Hasan Hüsnü
A 6.8-magnitude earthquake that occurred on January 24, 2020, has been effective in Turkey's eastern regions. The earthquake, with recorded peak ground acceleration (PGA) value of 0.292 g, caused the destruction or heavy damage of buildings, especially in the city center of Elazig province. The purpose of this paper was to share the results of detailed investigation in the earthquake-stricken area. Additionally, the causes of damages and failures observed in the buildings were compared to those that had occurred in previous earthquakes in Turkey. In this study, the damages observed in especially RC buildings as well as in masonry and rural buildings were summarized, the lessons learned were evaluated, and the results were interpreted with reference to Turkish earthquake codes. In the study, it was particularly emphasized why the building stock underwent such damage even though the buildings were exposed to earthquake acceleration well below the design acceleration values.
Citation - WoS: 11
Citation - Scopus: 9
Capture and Release Recyclable Dimethylaminomethyl-Calixarene Functional Cloths for Point-Of Removal of Highly Toxic Chromium Water Pollutants
(AMER CHEMICAL SOC, 2020) Bieber, Vera S.; Özçelik, Egemen; Cox, Harrison J.; Ottley, Christopher J.; Ratan, Jatinder K.; Karaman, Mustafa; Badyal, Jas Pal S.
Chromium(VI) contamination of drinking water arises from industrial activity wherever there is a lack of environmental legislation enforcement regarding the removal of such pollutants. Although it is possible to remove such harmful metal ions from drinking water through large-scale facilities, there currently exists no safe and simple way to filter chromium(VI) oxoanions at the point of use (which is potentially safer and necessary in remote locations or humanitarian scenarios). High-surface-area cloth substrates have been functionalized with calixarene molecules for the selective capture of aqueous chromium(VI) oxoanions in the presence of structurally similar anions. This is accomplished by pulsed plasmachemical deposition of a linker layer and subsequent functionalization with dimethylaminomethyl-calixarene (5,11,17,23-tetrakis [(dimethylamino)methyl]-25,26,27,28-tetrahydroxycalix[4]arene. Chromium(VI) oxoanions are captured by simply passing polluted water through the functionalized cloth, while other ions not harmful/beneficial to human health remain in the water. These cloth filters are simple to use, highly selective, and easily recyclable-thus making them attractive for point-of-use application in geographic regions lacking appropriate wastewater treatment plants or flawed environmental monitoring systems. Chromium(VI) pollutants have been successfully removed from real-world contaminated industrial wastewater streams using the dimethylaminomethyl-calixarene functionalized cloths.
Citation - WoS: 16
Citation - Scopus: 21
Carcinogenic-Potential Ecological Risk Assessment of Soils and Wheat in the Eastern Region of Konya (turkey)
(SPRINGER HEIDELBERG, 2021) Öztürk, Alican; Arıcı, Ömer Kağan
The drainage channel where the wastewater of Konya city center is discharged, the solid waste storage center, the soils surrounding the industrial area, the potential accumulation of toxic elements (PTE) accumulated in the wheat grown in these soils, and their effects on human health were examined. Between 1977 and 2010, the water in the drainage channel was used for a variety of crops, mainly wheat grown in the nearby agricultural areas until the commissioning of the wastewater treatment plant. Industrial facilities, solid waste landfills, and military firing areas are actively used and are thought to be important factors in heavy metal accumulation in soils. In addition, the investigation area is on the sediments of the deposits stored in the large Konya Lake depending on the geological structure around Konya and caused geogenic heavy metal accumulation as a result of the separation and transportation of ophiolitic, magmatic, metamorphic, and sedimentary rocks in the region. In the research, PTE accumulation was determined in the samples of N1 (Pb, As, and Hg), N9 (Cd, As), and N10 (Cd and As) and N8 (Pb) in wheat. The carcinogenic risk factor of Ni, Al, Mn, and Cr elements in the territory of the region has been found as medium for children and adults. It has been determined that the potential source of toxic elements does not only depend on anthropogenic events but also occurs as a result of geological events.
Citation - WoS: 37
Citation - Scopus: 38
Characteristics and High Temperature Wear Behavior of Chrome Vanadium Carbide Composite Coatings Produced by Thermo-Reactive Diffusion
(ELSEVIER SCIENCE SA, 2020) Günen, Ali; Kalkandelen, Müge; Gök, Mustafa Sabri; Kanca, Erdoğan; Kurt, Bülent; Karakaş, Mustafa Serdar; Çetin, Melik
In this study, Cr-V-C composite carbide layers were grown on the surface of a GGG-80 ductile iron using thermoreactive diffusion (TRD). The TRD process was carried out at temperatures of 900, 1000, and 1100 degrees C for 1 h using nano-sized Fe-V and Fe-Cr powders. The coatings were characterized by X-ray diffractometry (XRD), 2D profilometry, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), microhardness measurements, nanoindentation, and wear tests. The wear tests were performed on untreated and coated samples using a ball-on-disc type wear tester under 10 N load at four different temperatures (25 degrees C, 250 degrees C, 500 degrees C and 750 degrees C) against a 6-mm WC ball. Metallographic investigations revealed that the graphite nodules near the surface were dissolved as a result of the TRD process. Depending on the TRD process temperature, a coating with a thickness of 12-36 mu m, hardness of 24.14-31.38 GPa, and elastic modulus of 198-233 GPa was obtained. An increase in process temperature increased the thickness, hardness, and elastic modulus of the obtained Cr-V-C layers, which resulted in low friction coefficient values and decreased wear rates. Although all coated samples showed improved wear resistance in all wear test conditions, the wear rates were significantly increased at 750 degrees C due to flaking.

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