Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Bolat, Hakan(2)
- Adanur, Süleyman(1)
- Akgül, Halil İbrahim(1)
- Altunişik, Ahmet Can(1)
- Büyükgüngör, Orhan(1)
- Demircioǧlu, Zeynep(1)
- Erkus, Pinar(1)
- Genç, Ali Fuat(1)
- Günaydin, Murat(1)
- Işseven, Turgay(1)
- Kahyaoglu, Talip(1)
- Kaya, Afşin Ahmet(1)
- Kaya, Elif Çelenk(1)
- Kayln, Sercan(1)
- Kotan, Tuba Erkaya(1)
- Senaslan, Fatih(1)
- Taşdemir, Muharrem(1)
- Topal, Umut(1)
- Tuncer, Ertan(1)
- Tunç, Merve T.(1)
- Uzman, Ümit(1)
- Vural, Alaaddin(1)
- Yesevi Okur, Fatih(1)
- Çelik, Ayhan(1)
- Çullu, Mustafa(1)
- Ürkek, Bayram(1)
- Şengül, Mustafa(1)
Yayınlar
- MakaleAçık Erişim2024Identification of magnetic mineralogy and paleo-flow direction of the Miocene-quaternary volcanic products in the north of Lake Van, Eastern Turkey
Kayln, Sercan; Işseven, Turgay
One of the major challenges facing geochemistry, petrology, and volcanology researchers is the difficulty in determining the origin and paleo-flow directions of igneous and volcanic rocks. It is not possible to clearly determine origins and paleo-flow directions in areas with numerous volcanic centers. Anisotropy of magnetic susceptibility (AMS) is a valuable method that provides insights into the origins and paleo-flow directions of lavas that are complex to study. The presence of volcanic materials with thicknesses up to 1 km, coming from different sources at varied time intervals in the north of Lake Van, makes this area an ideal setting for implementing AMS in establishing paleo-flow directions. This study presents the magnetic mineralogy and AMS analysis of volcanic rocks from the Miocene to the Quaternary in the Lake Van region. We conducted isothermal remanent magnetization (IRM) and high-temperature susceptibility (HTS) studies to determine the magnetic mineralogy. IRM studies revealed that (titano)magnetite is responsible for the magnetization in most samples, while both (titano)magnetite and hematite are responsible for the rest. Alteration degrees and Curie temperatures of the rock samples were also determined through HTS measurements. There is good agreement between the anticipated directions of lava flow and our findings for nearly all volcanic rocks.
- MakaleAçık Erişim2021Investigation of corrosion and thermal behavior of PU-PDMS-coated AISI 316L
Taşdemir, Muharrem; Senaslan, Fatih; Çelik, Ayhan
Polydimethylsiloxane (PDMS) is widely used from biomedical to industrial applications due to its nontoxic, hydrophobic, and transparent characteristics. PDMS has good thermal and adhesion properties; however, its mechanical properties are comparatively weak. Therefore, PDMS is blended with various polymers to effectively improve its mechanical properties. In this study, polyurethane (PU)-polydimethylsiloxane (PDMS) blended coatings of different concentrations were applied on the AISI 316L stainless steel surface. Their effects on corrosion and tribocorrosion properties were investigated in Ringer's solutions. The blended polymer coatings were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The thermal properties of samples were examined by TGA and DSC. The surface images and cross-sectional were investigated using scanning electron microscopy (SEM). Tribocorrosion tests were carried out at open circuit potential (OCP). It was determined that hydrophobicity and thermal stability of polymer coating increased, while corrosion resistance slightly decreased with the increasing PDMS concentration in the polymer blended. The friction coefficient of blends decreased as the PU concentration increased. As a result, it was determined that the polymer-coated samples containing up to 50% PDMS prevented corrosive wear under the OCP wear test in Ringer's solutions.
- MakaleYalnız künye2019Antioxidant Activity, Physiochemical and Sensory Characteristics of Ice Cream Incorporated with Sloe Berry (Prunus spinosa L.)
Ürkek, Bayram; Şengül, Mustafa; Akgül, Halil İbrahim; Kotan, Tuba Erkaya
The aim of this study was to determine the influence of sloe berry (SB) addition at different ratios on the physical, chemical, antioxidant, colour and sensory properties and mineral contents of ice creams. The increment of SB led to the an increase of titratable acidity, overrun, viscosity and ash values, first dripping and complete melting times; in contrast, it decreased the total solid, pH and fat values. Mn and Zn values were affected significantly (P < 0.05) by the addition of SB but other element levels were not affected. L* and b* values decreased significantly in all samples as compared with control sample, while a*, H°, C* and ∆E* increased significantly with addition of SB. Antioxidant activity was the highest in the sample containing 15 % SB (w/w) among ice cream samples. The ice cream samples containing 15 % SB had higher score than the control sample in terms of colour and appearance, gumming structure and general acceptability.
- MakaleYalnız künye2018Ambient Vibration-Based System Identification of a Medieval Masonry Bastion for Health Assessment using Nonlinear Analyses
Altunişik, Ahmet Can; Genç, Ali Fuat; Günaydin, Murat; Adanur, Süleyman; Yesevi Okur, Fatih
Earthquakes have underlined the need for health monitoring and safety assessment of engineering structures in general and especially historical heritage. These structures can be exposed to many different loads such as earthquake and wind that may cause the deterioration and loss of structural integrity. In this study, ambient vibration-based system identification of Zaǧanos Bastion is carried out for health assessment using linear and nonlinear analyses. 3D finite element analyses of the bastion are performed using relievo drawings and analytical dynamic characteristics are obtained. Ambient vibration tests are conducted on the bastion and experimental dynamic characteristics such as natural frequencies, mode shapes and damping ratios are determined. Enhanced Frequency Domain Decomposition Method in the frequency domain and Stochastic Subspace Identification Method in the time domain are used to extract the experimental dynamic characteristics. Maximum differences are minimized using some uncertain parameters to obtain the updated finite element model. Linear and nonlinear time history analyses are carried out using 1999 Kocaeli earthquake ground motion record to display the maximum displacements, stresses and local damage regions with detail. This study suggests that minor damage at the connection points and exterior surface will sustain under destructive earthquakes.
- MakaleAçık Erişim2017Synthesis, spectroscopic characterization, X-ray structure and DFT calculations of Ni(II)bis(3,4 dimethoxybenzoate)bis(nicotinamide) dihydrate
Kaya, Elif Çelenk; Kaya, Afşin Ahmet; Demircioǧlu, Zeynep; Büyükgüngör, Orhan
A single crystal of Ni(II)bis(3,4 dimethoxybenzoate)bis(nicotinamide) dihydrate, formulated as C30H34N4NiO12 (I), was characterized in the solid state by infra-red (IR), ultra-violet (UV) and single crystal X-ray diffraction analysis at 296 K as mononuclear with a distorted octahedral stereochemistry. The complex consists of a six-coordinate Nickel atom in a distorted octahedral environment constructed from two N atoms and four O atoms and crystallizes in the monoclinic space group C 2/c with a=27.7680(16) Å, b=8.5748(3) Å, c=17.8018(9) Å, α=90°, β=108.154(4)°, γ=90°, Z=4. The molecular structure and geometry was also optimized using the B3LYP density functional theory method employing the 6-31G(d) basis set. The molecular electrostatic potential (MEP), frontier molecular orbitals (FMO) analysis, nonlinear optical properties (NLO) and natural bond analysis (NBO), Mulliken population analyis, natural population analysis (NPA) and Fukui function analysis were also described.
- MakaleYalnız künye2016Improving Rheological and Baking Properties of Gluten-Free Breads Using Defatted Hazelnut Flour with Various Gums
Tunç, Merve T.; Kahyaoglu, Talip
Defatted hazelnut flour (DHF) in different levels (5%, 10% and 15%) of locust bean, guar and xanthan gum were added in rice-based gluten-free formulations to improve rheological properties of dough and baking properties of bread. The rheological characteristics of dough samples were determined by steady flow curves and dynamic tests. The baking properties of breads were evaluated by specific volume, Textural Profile Analysis (TPA) parameters and color values. The rheological measurements showed that all gluten-free dough had pseudoplastic behavior. Specific volume values of breads ranged from 2.20 to 2.83cm3/g. Gum addition enhanced the specific volume of gluten-free breads. Hardness values of gluten-free breads ranged from 1,069.80 to 3,135.88 g and DHF addition of gluten-free formulations caused significant decrease of the hardness values of breads (p < 0.05). DHF addition in gluten-free formulations made bread crumb darker than bread without DHF and gum. DHF addition also increased a and b values of gluten-free bread's crumb.
- MakaleAçık Erişim2016Use of polyvinyl chloride (PVC) powder and granules as aggregate replacement in concrete mixtures
Bolat, Hakan; Erkus, Pinar
Concrete is one of the materials in which polymer wastes are utilized. Generally, these wastes are added at specific rates in scientific studies but an important problem of waste polymers is size irregularity. Even when consistent dosage rates are used, variations in polymer size can lead to variability in the physical and mechanical properties of the concrete produced. The aim of this study is to determine physical and mechanical properties of polyvinyl chloride (PVC)-containing concretes. In order to produce normal and high strength concretes, 10%, 20%, and 30% replacement ratios of PVC powder and granules by volume of aggregate are used. Slump, fresh and hardened densities, compressive strength, capillary water absorption, and abrasion were tested on all concrete types. As the PVC ratio increases, important changes are seen in all physical and mechanical concrete properties. The unit weights of the 10%, 20%, and 30% replacement PVC powder concretes are lower by ∼4%, 8%, and 13%, respectively, as compared to the reference mixtures, and the replacement PVC granule concretes are lower by ∼2%, 4%, and 7%. Compressive strength test results showed similar trends. As PVC replacement increases, the capillary water absorption decreases between 10% and 50%, and abrasion decreases between 27% and 77%.
- MakaleAçık Erişim2016Investigation of pozzolanic activity of volcanic rocks from the northeast of the Black Sea
Çullu, Mustafa; Bolat, Hakan; Vural, Alaaddin; Tuncer, Ertan
Mineralogical and chemical properties, as well as the pozzolanic activities, of the volcanic rocks in the northeast of the Black Sea were examined. Physical and mechanical tests were conducted on samples collected from the study area and the feasibility of using volcanic rocks as pozzolanic admixture in the concrete industry was investigated. Mortar samples containing admixture in the ratios of 0%, 10%, 20%, 30%, 40%, and 50% were prepared by keeping fineness of pozzolanic admixtures fixed. By using these mortar samples, prismatic mortar samples of 4×4×16 cm were prepared and the samples were cured in water. Their 7-, 28-, and 90-day tensile strengths, compressive strengths, and ultrasonic pulse velocity were determined. As a result, it was determined that volcanic rocks can be used to produce blended cement by considering their specific gravity, pozzolanic activities, and compressive strengths. It was noted that increase in trass rate significantly reduced tensile and compressive strength of cement in the early stage as expected.
- MakaleAçık Erişim2010Effect of rectangular/circular cutouts on thermal buckling load optimization of angle-ply laminated thin plates
Topal, Umut; Uzman, Ümit
This paper deals with thermal buckling load optimization of symmetrically laminated angle-ply thin plates with centrally located different cutouts subjected to a uniform temperature load rise. The optimum results are given for maximum buckling temperature and the fibre orientation is adopted as design variable. The results are obtained for the various cutout geometries such as rectangle and circle. The modified feasible direction (MFD) method is used for the optimization routine. Therefore a program based on FORTRAN is used. Finally, the effects of cutout areas, plate aspect ratios and boundary conditions on the optimum results are demonstrated.
- DergiInternational Journal of Nonlinear Sciences and Numerical Simulation
- DergiE-Polymers
- DergiOpen Geosciences
- DergiScience and Engineering of Composite Materials