Mühendislik ve Doğa Bilimleri Fakültesi Koleksiyonu

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

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Citation - WoS: 12
Citation - Scopus: 11
Aerodynamic Optimization of a Swept Horizontal Axis Wind Turbine Blade
(ASME, 2021) Kaya, Mehmet Numan; Köse, Faruk; Uzol, Oğuz; Ingham, Derek; Ma, Lin; Pourkashanian, Mohamed
The aerodynamic shapes of the blades are still of high importance and various aerodynamic designs have been developed in order to increase the amount of energy production. In this study, a swept horizontal axis wind turbine blade has been optimized to increase the aerodynamic efficiency using the computational fluid dynamics method. To illustrate the technique, a wind turbine with a rotor diameter of 0.94 m has been used as the baseline turbine, and the most appropriate swept blade design parameters, namely the sweep start-up section, tip displacement, and mode of the sweep have been investigated to obtain the maximum power coefficient at the design tip speed ratio. At this stage, a new equation that allows all three swept blade design parameters to be changed independently has been used to design swept blades, and the response surface method has been used to find out the optimum swept blade parameters. According to the results obtained, a significant increase of 4.28% in the power coefficient was achieved at the design tip speed ratio with the newly designed optimum swept wind turbine blade. Finally, baseline and optimum swept blades have been compared in terms of power coefficients at different tip speed ratios, force distributions, pressure distributions, and tip vortices.
Citation - WoS: 14
Citation - Scopus: 13
All-Dry Hydrophobic Functionalization of Paper Surfaces for Efficient Transfer of Cvd Graphene
(WILEY-V C H VERLAG GMBH, 2019) Çıtak, Emre; İstanbullu, Bilal; Şakalak, Hüseyin; Gürsoy, Mehmet; Karaman, Mustafa
In this study, the successful transfer of chemical vapor deposition (CVD)-grown graphene on an ordinary printing paper surface is demonstrated. Pristine paper is not a suitable substrate for graphene transfer because of its fragile and hydrophilic nature against the chemicals used during the transfer process. Two different fluoroalkyl polymers, namely poly(hexafluorobutyl acrylate) (PHFBA) and poly(perfluorodecyl acrylate) (PPFDA) are coated on paper surfaces by an initiated CVD (iCVD) technique to make the paper surfaces hydrophobic. Hydrophobicity is found to be an important factor in order for the graphene to be transferred onto the paper substrate. Although surfaces coated with PPFDA possess better hydrophobicity owing to their longer perfluoroalkyl group and higher roughness, the graphene transfer is found to be more successful on a PHFBA-coated surface. A thin film of PHFBA on the paper surface acts as a prime layer for effective and defect-free transfer of graphene and makes the paper surface ideal and robust during the graphene transfer process. The as-transferred graphene layer on the PHFBA-coated paper surface shows high conductivity values, even after repeated folding and flattening cycles.
Citation - WoS: 23
Citation - Scopus: 24
All-Dry Patterning Method To Fabricate Hydrophilic/Hydrophobic Surface for Fog Harvesting
(SPRINGER, 2020) Gürsoy, Mehmet
Inspired by natural creatures that live in the arid climate, fog harvesting can be an efficient approach to overcome freshwater scarcity. Fog harvesting ability of the creatures is mainly based on wettability differences of their surfaces. In this study, inspired by creatures that have hydrophilic regions surrounded by hydrophobic areas, a novel all-dry patterning method was applied to fabricate hydrophilic/hydrophobic patterned surfaces for fog harvesting. For this purpose, patterned surfaces were produced using plasma-enhanced chemical vapor deposition (PECVD) method with the help of a commercial magnet and iron powders. The idea behind the use of the magnetic field during PECVD deposition is to hold light iron particles on the substrate under the vacuum environment for masking substrate surface. For the first time, the magnetic field was used to fabricate patterned surfaces in vapor-phase polymerization. Ordinary glass slides were successfully transformed into hydrophilic/hydrophobic patterned glasses. The obtained results showed that the combination of hydrophobic and hydrophilic regions improved the fog harvesting performance.
Citation - WoS: 7
Citation - Scopus: 8
An Analysis of the Effect of Pressure Angle Change on Bending Fatigue Performance in Asymmetrical Spur Gears
(SAGE PUBLICATIONS LTD, 2021) Demet, Seyit Mehmet; Ersoyoğlu, Ali Serhat
In this study, the fatigue performances of symmetrical and asymmetrical spur gears were analyzed by performing single tooth bending fatigue tests. The gears tested were determined to be symmetrical spur gears with a 20 degrees/20 degrees pressure angle, asymmetrical spur gears with a 20 degrees/22 degrees pressure angle, and asymmetrical spur gears with a 20 degrees/25 degrees pressure angle. These gears were made of AISI 4140 material. Single tooth bending fatigue tests were performed under variable loads. Considering the tests performed at the same torque values in asymmetrical spur gears with a 20 degrees/22 degrees pressure angle compared to symmetrical spur gears with a 20 degrees/20 degrees pressure angle, a statistically significant increase in performance was achieved at close to 90%. While gears with 20 degrees/20 degrees and 20 degrees/22 degrees pressure angles break at the tooth root, tooth flank fracture was observed in relatively high numbers of cycles in asymmetric spur gears with a 20 degrees/25 degrees pressure angle. It was observed that the formation of tooth flank damage negatively affected the fatigue performance.
Ankara-yozgat Hattında Mühendislik ve Cbs Amaçlı Yaklaşıkjeoit Hesabı
(2019) Kahveci, Muzaffer; Tuşat, Ekrem; Yıldız, Ferruh; Sarı, Fatih; Mikailsoy, Fariz
Global Konum Belirleme Sistemlerinin (GNSS) çok yüksek doğruluklar sağlamaya başlamasıyla birlikte, uygulamada kısa sürede yüksek doğruluklu jeoit yüksekliklerinin elde edilmesi gereksinimi de önemli ölçüde artmıştır. Örneğin, mühendislik uygulamalarında ve CBS çalışmalarında ortometrik yükseklikler kullanıldığı için yerel jeoit belirleme çalışmaları daha da önem kazanmıştır. Bilindiği gibi Türkiye tektonik olarak aktif bir bölgede olup, farklı zamanlarda meydana gelen depremler ülke nivelman ağındaki noktaların düşey konumlarında deformasyonlara/değişimlere neden olmaktadır. Diğer taraftan Ülke Temel Jeodezik Ağlarının kurulması ve yaşatılmasından sorumlu olan Harita Genel Müdürlüğü (HGM; eski adıyla Harita Genel Komutanlığı), 1999 yılından bu yana GNSS ölçülerinden yararlanarak farklı yıllarda güncel Türkiye Jeoidi modelleri hesaplayarak, kullanıcıların hizmetine sunmaktadır. HGM tarafından bu güne kadar hesaplanmış olan jeoit modellerinin dış doğrulukların genel olarak 10 cm’den daha iyi olmadığı değerlendirilmektedir. Oysa kullanıcıların ihtiyacı olan bu doğrulukların 10 cm’den daha iyi olması arzu edilen bir durumdur. Söz konusu doğruluklara ulaşılıp ulaşılamayacağının araştırılması için Selçuk Üniversitesi olanakları ile pilot bir uygulama yapılması hedeflenmiş ve bu amaçla sadece İç Anadolu’nun belirli bir kesimini kapsayacak yerel gravimetrik jeoit ve geometrik yaklaşımla yaklaşık(quasi)-jeoit hesaplanması için Konya Selçuk Üniversitesi kaynakları kullanılarak bir bilimsel araştırma projesi başlatılmıştır. Söz konusu proje bölgesine ilişkin mevcut GNSS ve nivelman verilerine ilaveten gravite verileri arazide ölçülmüş ve mutlak gravite değerleri, TG-03 kestirim değerleri gibi bazı diğer veriler de HGM’den temin edilmiştir. Yerel quasi-jeoit hesabında Karlsruhe Üniversitesi Uygulamalı Bilimler Enstitüsü tarafından geliştirilmiş ve proje kapsamında temin edilmiş olan DFHRS (Sonlu Elemanlı Yükseklik Referans Sistemi) yazılımı kullanılmıştır. Söz konusu yazılım sürekli polinomsal yükseklik referans sistemi ve GNSS ile elde edilen elipsoidal yüksekliklere dayalı olarak jeoit yüksekliklerinin N(?, ?, h) parametrik modellenmesi prensibine dayanmaktadır. Bu yazılım ile yapılan hesaplama sonucunda 10 cm’den daha iyi doğruluklu yerel quasi-jeoit elde edilmesi sağlanmıştır. Aynı noktalardaki GPS/Nivelman jeoidi, DFHRS hesap ve TG-03 kestirim değerleri birbirleriyle karşılaştırılmıştır. Netice olarak, bu makalede proje kapsamında sadece geometrik yaklaşımla hesaplanmış olan quasi-jeoit modeline ilişkin yapılmış olan çalışmalar ile ulaşılmış olan ara sonuçlar sunulmaktadır.
Citation - WoS: 8
Citation - Scopus: 7
Ann Estimation Model for Photogrammetry-Based Uav Flight Planning Optimisation
(TAYLOR & FRANCIS LTD, 2022) Makineci, Hasan Bilgehan; Karabörk, H.; Durdu, A.
Artificial intelligence (AI) is undergoing a ground-breaking period. Recently, AI affects almost every part of human life. Using AI in path planning for Unmanned Aerial Vehicle (UAV) attracts attention as a novel need. The inputs that form the base of UAV use in photogrammetry are UAV Type (UT), Ground Sampling Distance (GSD), Overlap Rates (OR), and Atmospheric Conditions (AC). Input parameters directly impact the UAV's Flight Time (FT) and Battery Status (BS). Weighting and optimizing these parameters are the main ideas of this study. The effects of input values (GSD, OR, UT, AC) on the outputs (BS and FT) were optimized using Artificial Neural Networks (ANN) in this study. For the analysis, results have been produced in which different training algorithms are preferred (Gradient Descent - GD - and Levenberg-Marquardt - LM). The GD algorithm has reached 77.65% accuracy in FT estimation and 80.91% estimation accuracy on normalized data on the BS. Then, the correlation between the produced model and the input parameters and the output parameters was determined, and the weights of the inputs were revealed. As a result, it was determined that the AC parameter has the most significant effect on BS and FT. Also, it has been identified that the normalization process has a considerable impact on optimization.
Citation - WoS: 8
Citation - Scopus: 8
Application of the Central Composite Design and Response Surface Methodology for Investigation of Induction Time, Conjugated Diene, Conjugated Triene and Trans Fatty Acid Content of Corn Oil Enriched With Carotenoids
(SPRINGER, 2020) Topkafa, Mustafa
The central composite design technique was used to investigation of induction time, conjugated diene, conjugated triene and trans fatty acid content of corn oil enriched with lutein, beta-carotene and lycopene in this study. The levels of lutein and beta-carotene and were between 0 and 94 mg/kg, while lycopene levels was 0-49.56 mg/kg. Oil samples with and without lutein, beta-carotene and lycopene were prepared according to central composite design. The influence of these three independent variables on the four dependent variables such as time, conjugated diene and conjugated triene and trans fatty acid content was evaluated using a reduced cubic model. The each independent variable was effective on the induction time, conjugated diene, conjugated triene and trans fatty acid content of corn oil. The positive effect on the induction time was observed high concentrations of lutein and lycopene concentrations. Lutein, beta-carotene and lycopene had a significant effect on conjugated diene, conjugated triene and trans fatty acid content. The desirability function and the 3D plots suggested that optimum parameters were lutein concentration of 19 mg/kg, beta-carotene concentration of 19 mg/kg and lycopene concentration of 12.5 mg/kg as optimum parameters for maximum induction time and the minimum formation of conjugated diene, conjugated triene and trans fatty acid species.
Citation - WoS: 25
Citation - Scopus: 25
Application of Various Carboxylic Acids Modified Walnut Shell Waste as Natural Filler for Epoxy-Based Composites
(WILEY, 2021) Albaker, Ruya Isam Bakr; Kocaman, Süheyla; Martı, Mustafa Esen; Ahmetli, Gülnare
In this study, chemically modified walnut shells (WS) were used as the filling material for synthesis of bio-based epoxy composites and added to the matrix at varied mass ratios (10%-50%). The shells were initially treated with alkali and then modified with three different organic acids (citric acid [CA], oxalic acid [OA], and formic acid [FA]). The WS were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDX) and thermo gravimetric analyzer. The SEM and X-ray diffraction were employed to observe the morphology of the composites. The influences of acid type and WS percentages on the mechanical, thermal and water sorption properties were investigated. The maximum tensile strength (124.8 MPa) was obtained with CA-treated shells (CA-WS) and followed by OA-treated shells (OA-WS) (117 MPa) and FA-treated shells (FA-WS) (96.5 MPa). Acid modification had a positive effect on Young's modulus as that of epoxy resins increased by 5.45%-50.91%. The treatment did not significantly affect hardness. The optimum amount of modified shells in the composites was found to be 20 wt%. Water sorption values changed in the range of 2.78%-3.42% for composites with 20 wt% WS and observed to increase with the filler amount in the composite. However, this trend and the slight decrease in thermal properties are not critical obstacles for the use of modified WS in the manufacture of inexpensive epoxy- and bio-based eco-friendly products.
Citation - WoS: 1
Citation - Scopus: 3
An Approach for Learning From Robots Using Formal Languages and Automata
(EMERALD GROUP PUBLISHING LTD, 2019) Aslan, Muhammet Fatih; Durdu, Akif; Sabancı, Kadir; Erdogan, Kemal
Purpose In this study, human activity with finite and specific ranking is modeled with finite state machine, and an application for human-robot interaction was realized. A robot arm was designed that makes specific movements. The purpose of this paper is to create a language associated to a complex task, which was then used to teach individuals by the robot that knows the language. Design/methodology/approach Although the complex task is known by the robot, it is not known by the human. When the application is started, the robot continuously checks the specific task performed by the human. To carry out the control, the human hand is tracked. For this, the image processing techniques and the particle filter (PF) based on the Bayesian tracking method are used. To determine the complex task performed by the human, the task is divided into a series of sub-tasks. To identify the sequence of the sub-tasks, a push-down automata that uses a context-free grammar language structure is developed. Depending on the correctness of the sequence of the sub-tasks performed by humans, the robot produces different outputs. Findings This application was carried out for 15 individuals. In total, 11 out of the 15 individuals completed the complex task correctly by following the different outputs. Originality/value This type of study is suitable for applications to improve human intelligence and to enable people to learn quickly. Also, the risky tasks of a person working in a production or assembly line can be controlled with such applications by the robots.
Citation - WoS: 5
Citation - Scopus: 3
Ar-Ar Geochronology and Sr-Nd Isotopic Systematics of the Post-Collisional Volcanic Rocks From the Karapinar-Karacadag Area (central Anatolia, Turkey): an Alternative Model for Orogenic Geochemical Signature in Sodic Alkali Basalts
(Ceska Geologicka Spolecnost, 2022) Gençoğlu Korkmaz, Gülin; Kurt, Hüseyin; Asan, Kürşad; Leybourne, Matthew
The Plio???Quaternary post-collisional volcanism in the Karap??nar area is represented by two occurrences: (1) Karacada?? Volcanic Complex (KCVC) and (2) Karap??nar Volcanic Field (KPVF). The investigated volcanic units are the southwes-tern part of the Neogene to Quaternary Cappadocia Volcanic Province (CVP) in Central Anatolia. The CVP generally displays calc???alkaline affinity in the Late Miocene to Pliocene rocks, but both calc-alkaline and sodic alkaline affinity in the Plio???Quaternary rocks, all of which have an orogenic geochemical signature. Such a volcanic activity contradicts the Western and Eastern Anatolian volcanism characterized by anorogenic OIB-like sodic alkaline volcanic rocks postdating early orogenic calc???alkaline ones. We hypothesize that such temporal and geochemical variations in the investigated rocks result from crustal contamination and present major and trace element chemistry and Sr???Nd???Pb???O isotope geochemistry, coupled with 40Ar/39Ar geochronology data to restrict the genesis and evolution of the rocks. The Neogene Karacada?? volcanic rocks are represented by lava flows, domes and their pyroclastic equivalents constituting a stratovolcano, and dated by new 40Ar/39Ar ages of 5.65 to 5.43 Ma. They are mainly composed of andesitic, rarely basaltic, dacitic and trachytic rocks and have a calc???alkaline character. Constituting a monogenetic volcanic field, the Quaternary Karap??nar volcanic rocks are typically formed by cinder cones, maars and associated lavas, including xenoliths and xenocrysts plucked from the Karacada?? rocks. They comprise basaltic to andesitic rocks with a transitional affinity, from sodic alkaline to calc???alkaline. Both the Karacada?? and Karap??nar volcanic rocks display incompatible trace element patterns rather characteristic for orogenic volcanic rocks. The Sr, Nd and Pb isotopic systematics of both units show a relatively narrow range, but their ??18O values are markedly different. The Karacadag volcanic rocks have ??18O values ranging from 7.5 to 8.9 ???, resembling those of subduction-related basalts, but the Karap??nar volcanics have ??18O ratios between 5.7 and 6.5 ??? corresponding to OIB-like rocks. Additionally, ??18O values and 87Sr/86Sr ratios correlate positively with SiO2 in the rocks, indicating that contamination played an important role during differentiation processes. All the data obtained suggest that the Karacada?? basaltic rocks stemmed from a subduction-modified lithospheric mantle source. On the other hand, the origin of the Karap??nar basaltic rocks can be explained in terms of OIB-like melts contaminated with the Karacada?? volcanic rocks to gain orogenic geochemical signature, which may be an alternative model for the origin of the CVP sodic alkali basalts.
Citation - WoS: 16
Citation - Scopus: 17
Assessment of Natural Radioactivity Level of Soil and Water in the Region of Corlu (turkey)
(SPRINGER, 2021) Manisa, Kaan; Erdoğan, Mehmet; Usluer, Ali; Çetinkaya, Hakan; Işık, Ulaş; Şahin, Latife; Zedef, Veysel
The activity concentrations of Rn-222 with an AlphaGUARD system in well having different depths and in natural spring waters were measured to assess the natural radioactivity level of the corlu region. The measured concentrations varied from 22.04 to 63.92 Bq L-1 for 6 well water samples, 15.38-24.33 Bq L-1 for 6 spring water samples. The activity concentrations from U-238, Th-232 and K-40 in 11 soil samples collected from the same region were also determined and the outdoor gamma dose rates at 1 m above the surface at the same sampling points were measured. The results obtained in this study lie within safe limits recommended by WHO and UNSCEAR with the exception of the mean specific activity of K-40 radionuclide.
Citation - WoS: 6
Citation - Scopus: 7
Automated Elimination of Eog Artifacts in Sleep Eeg Using Regression Method
(2019) Dursun, Mehmet; Özşen, Seral; Güneş, Salih; Akdemir, Bayram; Yosunkaya, Şebnem
Sleep electroencephalogram (EEG) signal is an important clinical tool for automatic sleep staging process. Sleep EEG signal is effected by artifacts and other biological signal sources, such as electrooculogram (EOG) and electromyogram (EMG), and since it is effected, its clinical utility reduces. Therefore, eliminating EOG artifacts from sleep EEG signal is a major challenge for automatic sleep staging. We have studied the effects of EOG signals on sleep EEG and tried to remove them from the EEG signals by using regression method. The EEG and EOG recordings of seven subjects were obtained from the Sleep Research Laboratory of Meram Medicine Faculty of Necmettin Erbakan University. A dataset consisting of 58 h and 6941 epochs was used in the research. Then, in order to see the consequences of this process, we classified pure sleep EEG and artifact-eliminated EEG signals with artificial neural networks (ANN). The results showed that elimination of EOG artifacts raised the classification accuracy on each subject at a range of 1%– 1.5%. However, this increase was obtained for a single parameter. This can be regarded as an important improvement if the whole system is considered. However, different artifact elimination strategies combined with different classification methods for another sleep EEG artifact may give higher accuracy differences between original and purified signals.
Citation - WoS: 2
Citation - Scopus: 1
Bernstein-Walsh Polynomial Inequalities in Domains Bounded by Piecewise Asymptotically Conformal Curve With Nonzero Inner Angles in the Bergman Space
(SPRINGER, 2019) Abdullayev, F.G.; Abdullayev, G.A.; Şimşek, Dağıstan
We continue our investigation of the order of growth of the modulus of an arbitrary algebraic polynomial in the Bergman weight space, where the contour and weight functions have certain singularities. In particular, we deduce a Bernstein-Walsh-type pointwise estimate for algebraic polynomials in unbounded domains with piecewise asymptotically conformal curves with nonzero inner angles in the Bergman weight space.
Citation - WoS: 5
Citation - Scopus: 7
Biochar Produced From Co-Pyrolysis of Olive Pomace & Crude Oil as an Adsorbent for Cr (vi) Removal From Aqueous Solutions
(Iranian Institute of Research and Development in Chemical Industries, 2022) Almezgagi, Maha; Kaya Güzel, Gülcihan; Kar, Yakup; Deveci, Hüseyin
This study investigated aqueous solution treatment to remove Cr (VI) using a biochar-based adsorbent. Olive pomace and crude oil were used to synthesize the biochar adsorbent via co-pyrolysis for the first time. The biochar properties were examined with Fourier Transform Infra-Red (FT-IR) spectroscopy, scanning electron microscopy (SEM), and Energy Dispersive X-ray (EDX) analyses before and after adsorption. The adsorption experiments were carried out in a batch process under different experimental conditions. The optimum adsorption efficiency was experimentally found to be at pH of 1.5, contact time of 15 min, Cr (VI) initial concentration of 20 mg/L, adsorbent dose of 0.4 g, and 303 K. Langmuir and Freundlich isotherms were used to evaluating the adsorption performance of biochar, and the Langmuir isotherm model was well fitted to experimental data with a maximum adsorption capacity of 9 mg/g. Kinetic experimental data was best described using a pseudo-second-order kinetic model. The thermodynamic parameters of the adsorption process were examined in detail, and the process was exothermic and spontaneous in nature. It is concluded that biochar can be successfully used as an adsorbent for the treatment of Cr (VI) contaminated water. Additionally, the evaluation of olive pomace provided not only a decrease in waste accumulation in the olive production industry but also the synthesis of an inexpensive and environmentally friendly adsorbent. © 2022, Iranian Institute of Research and Development in Chemical Industries. All rights reserved.
Citation - WoS: 36
Citation - Scopus: 39
Boron Removal and Antifouling Properties of Thin-Film Nanocomposite Membrane Incorporating Pecvd-Modified Titanate Nanotubes
(WILEY, 2019) Ng, Zhi-Chien; Chong, Chun-Yew; Lau, Woei-Jye; Karaman, Mustafa; Ismail, Ahmad Fauzi
BACKGROUND Incorporation of nanofillers into the polyamide (PA) layer of thin-film composite (TFC) membrane could improve membrane surface properties for enhanced water separation efficiency. However, most nanofillers do not disperse well in organic medium. In this work, the surface of titanate nanotubes (TNTs) was modified via the plasma-enhanced chemical vapour deposition (PECVD) method in order to promote its dispersion rate (in organic medium) during thin-film nanocomposite (TFN) membrane fabrication. RESULTS Fourier transform infrared (FTIR) analysis confirmed the surface chemistry of TNTs coated by hexafluorobutyl acrylate (HFBA) or hydroxyethyl methacrylate (HEMA) via PECVD method. The effects of embedding modified TNTs into the PA layer on membrane surface morphology, hydrophilicity and performance were also investigated and the results were further compared with commercial reverse osmosis (RO) membranes. It was found that the incorporation of HFBA- and HEMA-modified TNTs could enhance the membrane water permeability by >25% and >40%, respectively, without compromising their salt rejection. The boron rejections of TFN membranes incorporated with HFBA- and HEMA-modified TNTs meanwhile were recorded at 75.56% and 70.73%, respectively; these values were relatively higher than those for the self-synthesized TFC (68.57%) and commercial RO membranes (37-39%). The developed TFN membranes also exhibited higher fouling tolerance than the commercial RO membranes, achieving >94% of water flux regeneration as a result of enhanced membrane surface hydrophilicity. CONCLUSION Compared to hydrophilic modification using HEMA, nanofillers modified by hydrophobic HFBA proved more effective at producing a PA layer with better nanofiller distribution, making the resultant TFN membrane more suitable for desalination processes. (c) 2019 Society of Chemical Industry
Boru Hattı Kamulaştırma Çalışmalarında Karşılaşılan Teknik, Ekonomik, Hukuki Sorunlar ve Çözüm Önerileri
(Mersin Üniversitesi, 2019) İşcan Fatih; Vargeloğlu Fatih
Enerji nakil hattı projeleri, petrol boru hattı projeleri, tren yolları, otoyollar gibi kamu hizmetlerinin hayata geçirilebilmeleri için gerekli arazilerin ya kamu malı olması ya da kamuya mal edilmesi gerekmektedir. Ancak kamunun elinde bu projeler için gerekli araziler çoğu zaman ihtiyaçlara cevap verebilecek büyüklük ve uygunlukta bulunmamaktadır. Bu hizmetler için gereksinim duyulan ve kamuya ait olmayan taşınmazların kamuya mal edilmesi Anayasal güvence altındaki mülkiyet hakkını sınırlayıcı olan kamulaştırma işlemi ile gerçekleştirilebilmektedir. Kamulaştırma çalışmalarının uygulanması ise uzun ve detaylı işlemleri gerektiren bir süreçtir. Kamulaştırma işlemi gerçekleştirilirken hukuki, ekonomik ve teknik anlamda pek çok sorunla karşılaşılmaktadır. Kamu hizmetlerinin zamanında ve en ekonomik bir şekilde gerçekleştirilmesi için bu sorunların tespiti ve giderilmesi son derece önemlidir. Bu çalışmada, Trans Anadolu Doğalgaz Boru Hattı (TANAP )projesi özelinde boru hattı kamulaştırma çalışmalarında karşılaşılan teknik, ekonomik ve hukuki sorunlar irdelenmiş, hata kaynakları araştırılmış ve bu sorunlar için öneriler getirilmiştir. Yapılan çalışma sonucunda, eski teknolojiyle üretilen kadastral paftalardan kaynaklanan hataların, taşınmazların bedel tespitinde karşılaşılan sorunların ve yasal mevzuattaki eksikliklerin kamulaştırma faaliyetlerini olumsuz etkilediği görülmüştür. Kamulaştırma faaliyetlerinin bu olumsuzluklardan etkilememesi için genel olarak teknik anlamda sayısal altlıkların tek bir sistemde oluşturulması, ekonomik anlamda taşınmaz değerlemesi ile ilgili ilke ve usullerin yeniden değerlendirilmesi, hukuki açıdan da yasal mevzuattaki boşluk ve eksikliklerin giderilmesi gerekmektedir.
Cbs ve Ahp Yöntemi Yardımıyla Niğde Kenti Örneğinde Taşınmaz Değerleme
(2020) Bozdağ, Aslı; Ertunç, Ela
Taşınmaz değerlemesi tarafsız ve objektif bir şekilde, taşınmazın nitelik, çevre ve kullanım koşulları gibi etmenlerin değerlendirilmesi yoluyla söz konusu taşınmaza ait değerinin belirlenmesidir. Güvenilir bir taşınmazın değer tahmini arazi özelliklerinin tarafsız bir şekilde birlikte analizi ile mümkündür. Günümüzde halen taşınmaz değerlemesi ideal sistem olarak kurulamamıştır. Bundan dolayı da taşınmaz değerlerinde tutarsızlıklar meydana gelmekte ve taşınmaza değer biçebilmek için kullanılan kriterlerin etkili bir şekilde araştırılması gerekmektedir. Bu çalışmada taşınmaz mal olan yapıların değerlemesi için literatür araştırması sonrasında 5 ana kriter ve bu kriterlerle ilişkili 38 alt kriter belirlenmiştir. Niğde kentinin gelişme bölgesinde seçilen 30 dairenin taşınmaz değeri bu kriterlere göre yapı ve yapının konumsal özellikleri açısından değerlendirilmiş ve piyasa değerleriyle karşılaştırılmıştır. Yapıların değerlemesinde bu kriterlerin önem sıralamasını belirlemek için Çok Ölçütlü Karar Verme (ÇKKV) yöntemlerinden en yaygın kullanımı olan Analitik Hiyerarşi Prosesi (AHP) kullanılmıştır. Kriterlerin karşılaştırılması uzman görüşlerine göre yapılmış ve bu kriterlerin önem dereceleri ve istatistiksel olarak anlam düzeyleri hesaplanmıştır. Yapıların konumsal özelliklerin belirlenmesinde CBS yardımıyla yapılan analizlerden yararlanılmıştır. Sonuçta, seçilen 30 dairenin AHP ve CBS yöntemi kullanılarak yapılan puanlama yardımıyla taşınmaz değeri belirlenmiş ve bulunan bu değerler taşınmazların piyasa değerleri ile karşılaştırılmıştır. AHP ve CBS yardımıyla belirlenen taşınmaz değerlerinin piyasa değerleri ile uyumlu olduğu tespit edilmiştir.
Citation - WoS: 17
Citation - Scopus: 18
Chemical Modification of Apricot Kernel Shell Waste and Its Effect on Phenolic Novolac Epoxy Composites
(WILEY, 2020) Kocaman, Süheyla
Apricot kernel is one of the most abundant types of agro-waste in the eastern Anatolia regions of Turkey. In this study, apricot kernel shells (AKShs) were chemically modified using levulinic acid (LA) for the first time, and their potential for developing biobased composites was evaluated. Phenol novolac epoxy resin was used as matrix owing to its high thermal and superior adhesion properties. Shell treatments to improve interfacial bonding were carried out using alkali, acetic acid, and LA. These treatments were aimed at improving the mechanical properties, wettability, and bonding of the composites. Moreover, these treatments could prevent the deterioration of the fiber/matrix interface (hydrophilic and hydrophobic effect) and mitigate damage to the fiber during production, which is one of the main reasons for the reduced strength of the composites. The thermal characteristics, crystallinity index, chemical composition, and surface morphology of the untreated and chemically modified AKShs and composites were studied by thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy, respectively. In addition, the composites were analyzed in detail using mechanical tests and contact angle measurements. The chemical treatment using LA resulted in composites with superior mechanical behavior.
Citation - WoS: 13
Citation - Scopus: 15
Chemometric Approaches for the Characterization of the Fatty Acid Composition of Seventeen Mushroom Species
(TAYLOR & FRANCIS INC, 2020) Çayan, Fatih; Deveci, Ebru; Çayan, Gülsen Tel; Duru, Mehmet Emin
Mushrooms have been used since ancient times because of their nutritional, medicinal and economic potential. In this study, fatty acid compositions of seventeen mushroom species, naturally growing in Turkey, were determined by using gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Totally, twenty-four fatty acids were identified in mushroom species. Generally, oleic (6.76-59.25%), linoleic (6.45-61.63%), palmitic (3.57-28.09%) and stearic (0.90-19.77%) acids were identified as the main fatty acids in all studied mushroom species. Principal component analyses (PCA) and hierarchical clustering analyses (HCA) were applied to analyze the chemometry of twenty-four fatty acids of the seventeen mushroom species by using Minitab 16.0 software. The main fatty acid compounds found in the mushrooms and their concentrations have been effective in distinguishing mushroom species from each other. As a result of PCA and HCA analysis, it was determined that Daedalea quercina (DQ) was distinctly separated from other mushroom species in terms of fatty acid composition. This study reveals that the chemometric analysis by PCA and HCA techniques could be used for the classification of the mushroom species according to their fatty acid compositions.
Citation - WoS: 12
Citation - Scopus: 14
Chemometrics Evaluation of Phytochemicals and Antioxidant Activities of the Extracts of Chaerophyllum Bulbosum Roots and Aerial Parts
(TAYLOR & FRANCIS INC, 2022) Çayan, Gülsen Tel; Deveci, Ebru; Çayan, Fatih; Molo, Zeynep; Duru, Mehmet Emin; Yeşil, Yeter
The objective of this study was provide the first report to assess the high-performance liquid chromatography-diode array detection (HPLC-DAD) identification of phytochemicals, the spectrophotometric determination of total phenolics and flavonoids, and antioxidant activities of the root and aerial extracts of Chaerophyllum bulbosum. HPLC-DAD identified the main phytochemical to be rosmarinic acid in the roots in the acetone (CBRA) (13.98 +/- 0.12 mg/g) and the aerial water (CBAW) extract; myricetin (8.30 +/- 0.22 mg/g) in the root methanol extract (CBRM); trans-aconitic acid (6.46 +/- 0.49 mg/g) in the root water extract (CBRW) and fumaric acid in the aerial methanol (CBAM) (17.43 +/- 0.87 mg/g) and water CBAW (18.96 +/- 0.81 mg/g) extracts. The concentrations of total phenolics and flavonoids were 2.00 +/- 0.14-17.79 +/- 0.99 mu g PEs/mg extract and 2.90 +/- 0.00-27.64 +/- 0.37 mu g QEs/mg extract, respectively. The highest antioxidant activity was found in the root acetone extract (CBRA) using the beta-carotene-linoleic (IC50: 172.31 +/- 0.16 mu g/mL) and CUPRAC (A(0.50): 126.00 +/- 0.24 mu g/mL) assays and in the root water extract (CBRW) for DPPH center dot (IC50: 59.51 +/- 0.21 mu g/mL) and metal chelating (IC50: 65.91 +/- 0.36 mu g/mL) assays in the aerial water extract (CBAW) using the ABTS(center dot+) (IC50: 59.51 +/- 0.21 mu g/mL) assay. The relationship between the phytochemicals and antioxidant activities of the extracts was chemometrically determined by principal component analysis (PCA) and hierarchical cluster analysis (HCA).

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