Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Dertli, Enes(116)
- Şahin, Engin(48)
- Kaya, Yunus(46)
- Özen, Soner(46)
- İspirli, Hümeyra(45)
- Pat, Suat(44)
- Şenay, Volkan(42)
- Korkmaz, Şadan(36)
- Yilmaz, Mustafa Tahsin(33)
- Kutlu, Naciye(32)
- Cuce, Erdem(31)
- Öner, Erdal(31)
- Artar, Musa(30)
- Ertugrul, Mehmet(29)
- Hasar, Ugur Cem(29)
- Mercan, Emin(28)
- Bayraktar, Bülent(27)
- Bayram, Sinan(27)
- Can, Zehra(25)
- Ecem Bayram, Nesrin(25)
- Çolak, Murat(23)
- Özdemir, Akın(23)
- Cuce, Pinar Mert(22)
- Sert, Durmuş(22)
- Ayata, Ümit(21)
- Bayram, Ozkan(21)
- Dirican, Ebubekir(20)
- Abdioglu, Murat(19)
- Ayazoglu, Rabil(19)
- Birinci, Ahmet(19)
- Kamiloğlu, Aybike(19)
- Gerçek, Yusuf Can(18)
- Taylan, Osman(18)
- Tozlu, Alperen(18)
- Gul, Volkan(15)
- Hasar, Ugur C.(15)
- Kadakal, Mahir(15)
- Sagdic, Osman(15)
- Ergün, Mustafa(14)
- Kadakal, Huriye(14)
Yayınlar
- MakaleAçık Erişim2022Scopus SJRQ4Some Physical, Biological, Hardness, and Color Properties of Wood Impregnated with Propolis
Akçay, Çağlar; Ayata, Ümit; Birinci, Emre; Yalçın, Mesut; Kolaylı, Sevgi
Propolis is a bee product collected by honeybees from various tree species in nature. It has antifungal, antibacterial, antioxidant, and anticancerogenic properties. Recently, propolis has been used in wood protection area because it has antifungal properties and is a natural and environmentally friendly material. In this study, some deciduous wood species were treated with methanolic propolis extracts. Propolis solutions were prepared by dissolving propolis in methanol in concentrations of 0.5%, 2.5%, 5%, and 8%. These solutions were forced deep into the Scots pine (Pinus sylvestris L.), fir (Abies nordmanniana), and spruce (Picea orientalis L.) woodblocks under vacuum and pressure. Water uptake and water-repellent efficiencies of the woodblocks were tested at 2-, 4-, and 20-hour immersion periods. Sample blocks were tested against wood-destroying house borer (Hylotrupes bajulus) (Coleoptera, Cerambycidae) larvae for 21 weeks. In addition, color changes of woodblocks treated with propolis were determined. According to results obtained in the study, the highest water-repellent efficiency was 61.4% in propolis-impregnated spruce wood at concentration level of 8% during the 2-hour period. These results show that propolis extracts could be used as hydrophobic material for wood. Larvae mortality rates indicated that 8% concentration level was not adequate to overcome H. bajulus larvae or propolis is not effective against H. bajulus larvae. While L* value decreases with the increase of impregnation rate, a* and b* values increase in all wood types. As the impregnation rate increased, the total color difference also increased.
AtıfScopus2WoS2TR Dizin1
İncele - MakaleAçık Erişim2022Scopus SJRQ2Efficient bioreduction of cyclohexyl phenyl ketone by Leuconostoc pseudomesenteroides N13 biocatalyst using a distance-based design-focused optimization model
Özdemir, Akın; Şahin, Engin
Whole-cell biocatalysts have been a popular method for the preparation of chiral alcohols. Although asymmetric reduction of cyclohexyl(phenyl)methanone (1) by chemical catalysts is common, a biocatalytic asymmetric reduction is extremely rare. In this respect, we report herein that Leuconostoc pseudomesenteroides N13 was successfully employed as a biocatalyst to reduce 1 to (S)-cyclohexyl(phenyl)methanol ((S)-2). Furthermore, the use of a mathematical optimization strategy for asymmetric reduction of substrate 1 is not known in the current literature. The new distance-based design-focused optimization model was used to enhance the conversion of the substrate, enantiomeric excess (ee) of product, and yield. The distance-based design-focused optimization model identified the following optimal bioreduction conditions: pH=6.46, temperature=30°C, incubation period=72 hours, and agitation speed=199 rpm. Then it was stated that under these ideal conditions, (S)-2 may be produced with 99 % ee and 98.46 % conversion rate (cr). (S)-2 was achieved with 99% ee, and 99% cr as a consequence of the experimental reaction carried out under the indicated optimization conditions. It has been shown that Leuconostoc pseudomesenteroides N13 can be utilized as a biocatalyst in asymmetric reduction reactions. This study, in addition to being the first example of a bioreduction of substrate 1 by mathematical optimization, also demonstrates for the first time the distance-based design-focused model can be used in the bioreduction reaction.
AtıfScopus9WoS9OpenAlex8İncele - MakaleAçık Erişim2022Scopus SJRQ1Comparative seismic design optimization of spatial steel dome structures through three recent metaheuristic algorithms
Carbas, Serdar; Artar, Musa
Steel dome structures, with their striking structural forms, take a place among the impressive and aesthetic load bearing systems featuring large internal spaces without internal columns. In this paper, the seismic design optimization of spatial steel dome structures is achieved through three recent metaheuristic algorithms that are water strider (WS), grey wolf (GW), and brain storm optimization (BSO). The structural elements of the domes are treated as design variables collected in member groups. The structural stress and stability limitations are enforced by ASD-AISC provisions. Also, the displacement restrictions are considered in design procedure. The metaheuristic algorithms are encoded in MATLAB interacting with SAP2000 for gathering structural reactions through open application programming interface (OAPI). The optimum spatial steel dome designs achieved by proposed WS, GW, and BSO algorithms are compared with respect to solution accuracy, convergence rates, and reliability, utilizing three real-size design examples for considering both the previously reported optimum design results obtained by classical metaheuristic algorithms and a gradient descent-based hyperband optimization (HBO) algorithm.
AtıfScopus15WoS13OpenAlex15İncele - MakaleYayıncıda açık erişim2022Scopus SJRQ3Thiol disulfide homeostasis in primary dysmenorrhea
Savrun, Atakan; Savrun, Şeyda Tuba; Dirican, Ebubekir; Gökçen, Emre; Arıcı, Yeliz Kasko; Aygün, Ali; Korkmaz, Vakkas; Neşelioğlu, Salim; Erel, Özcan; Kıran, Tuğba Raika
Oxidative stress is defined as a result of the loss of balance between the production of free radical or reactive oxygen species and the antioxidant system. This study aimed to determine the level of thiol-disulfide homeostasis (TDH) in the serum of women with primary dysmenorrhea. The study group consisted of 42 subjects with primary dysmenorrhea, and the control group consisted of 30 volunteer women with demographic characteristics similar to the study group. Native thiol (SH), total thiol (TSH), disulphide (SS), and SH/SS parameters were measured for TDH of the subjects. The SH (p = 0.038) and SH/TSH (p = 0.046) levels were significantly higher while SS (p = 0.013), SS/SH (p = 0.042) and SS/TSH (p = 0.046) levels were lower in the study group than in the healthy control group. The SS cut-off value was determined as 17.85 in the study group (sensitivity = 61.9%, specificity = 43.3%). Therefore, the probability of dysmenorrhea may increase significantly when SS levels fall below this value. In subjects with dysmenorrhea, there was a decrease in SS levels and an increase in SH levels in order to protect the cells and tissues from the harmful effects of free radicals.
AtıfOpenAlex1İncele - MakaleAçık Erişim2022Scopus SJRQ1Conventional and Microcellular Injection Molding of a Highly Filled Polycarbonate Composite with Glass Fibers and Carbon Black
Yilmaz, Galip; Devahastin, Apichart; Turng, Lih-Sheng
Conventional solid injection molding (CIM) and microcellular injection molding (MIM) of a highly filled polycarbonate (PC) composite with glass fibers and carbon black were performed for molding ASTM tensile test bars and a box-shape part with variable wall thickness. A scanning electron microscope (SEM) was used to examine the microstructure at the fractured surface of the tensile test bar samples. The fine and uniform cellular structure suggests that the PC composite is a suitable material for foaming applications. Standard tensile tests showed that, while the ultimate strength and elongation at break were lower for the foamed test bars at 4.0–11.4% weight reduction, their specific Young’s modulus was comparable to that of their solid counterparts. A melt flow and transition model was proposed to explain the unique, irregular “tiger-stripes” exhibited on the surface of solid test bars. Increasing the supercritical fluid (SCF) dosage and weight reduction of foamed samples resulted in swirl marks on the part surface, making the tiger-stripes less noticeable. Finally, it was found that an injection pressure reduction of 25.8% could be achieved with MIM for molding a complex box-shaped part in a consistent and reliable fashion.
AtıfScopus2WoS2OpenAlex3
İncele - MakaleAçık Erişim2022Scopus SJRQ4Angle Conceptions of Students with Learning Disabilities and Hearing Impairments; [Öğrenme Güçlüğüne Sahip ve İşitme Engelli Öğrencilerin Açı Kavrayışları]
Güven Akdeniz, Dilşad; Gürefe, Nejla; Arikan, Ahmet
The angle concept is central to the development of geometry knowledge, which is important and functional for everyday life. In this context, the aim of this study was to examine the understanding of the angle concept of middle school students with learning disabilities (LDs) and hearing impairment (HI). The participants of this study, which was a case study, were identified with the criterion and convenience sampling methods. The participants were two students, one of whom with LDs and the other had a HI, each of whom was in grade 6. Data collected through individual clinical interviews with the students were analyzed using the cross-case analysis method. According to the findings of the study, the angle conception of both students was limited to the shape of the angle, and both students were aware of the concept of direction in the angle, but the student with the LD perceived the angle more statically, and did not have enough knowledge about the angle measurement or its unit. It was seen that the student with the HI confused the angle and angle measure, but was aware of the various angles according to their measures.
AtıfScopus2WoS1OpenAlex2İncele - MakaleAçık Erişim2022Scopus SJRQ4The effect of carvacrol on oxido-inflammatory ovarian injury and infertility induced by ischemia-reperfusion in rats
Sahin, Nurullah; Delibas, Ilhan Bahri; Isaoglu, Unal; Suleyman, Bahadir; Yazici, Gulce Naz; Coban, Taha Abdulkadir; Uzel, Kemine; Suleyman, Halis; Arslan, Veysel
Background: Increased oxidants and proinflammatory cytokines play a role in the pathogenesis of ovarian ischemia-reperfusion (OIR) injury and related infertility. Carvacrol has antioxidant, antibacterial and anti-inflammatory properties. Methods: Protective effect of carvacrol against ischemia-reperfusion (IR)-related ovarian damage and infertility was investigated. IR process were applied to the ovaries of rats, which were divided into the following groups (n = 12): OIR, IR +50 mg/kg carvacrol (IRC-50), IR +100 mg/kg carvacrol (IRC-100) and sham group (SG). After the reperfusion process, six rats from each group were killed and the removed ovaries were examined biochemically and histopathologically. The remaining animals were kept two months with mature male rats to reproduce. Results: At a dose of 50 mg/kg, carvacrol suppressed the oxidant parameter increase and antioxidant decrease caused by IR in ovarian tissue. At a dose of 100 mg/kg, carvacrol antagonized both oxidant and proinflammatory cytokine increase and antioxidant decrease. Histopathologically, severe degeneration of follicles in the ovaries of the OIR group, necrotic cell accumulations, hemorrhage in the corpus luteum, edema in the interstitial tissue, polymorphous nuclear leukocyte (PNL) infiltration, and congestion and dilation of blood vessels were detected. Inflammatory symptoms such as edema in the ovarian tissue, congested dilated blood vessels and PNL infiltration were observed at a dose of 50 mg/kg of carvacrol, but these histopathological findings were not observed at a dose of 100 mg/kg. Conclusion: A dose of 100 mg/kg carvacrol, which eliminated inflammatory damage, significantly prevented the development of IR-induced infertility. Carvacrol may be beneficial in the treatment of IR-related ovarian damage and infertility. Copyright:
AtıfScopus2WoS1OpenAlex2İncele - MakaleAçık Erişim2022Scopus SJRQ2Comparison of classical and newly designed motion profiles for motion-based control of flexible composite manipulator
Uyar, M.
The motion profiles defined to move the robot manipulators directly affect the endpoint position accuracy, position repeatability, and vibration control of the manipulators in engineering applications, especially in flexible manipulators. This study deals theoretically and experimentally with the dynamic performance of two different motion profiles in reducing the vibration amplitudes of a single-link flexible composite manipulator. Manipulator is produced from epoxy-glass composite material with a layer orientation of [0/90/0/0/90/0] lay-up. For theoretical studies, the SimMechanics-based flexible dynamic model is created using flexible beam block in MATLAB/Simulink, and the finite element model is established with a layered structural solid element in ANSYS. Two different motion profiles are defined to drive the manipulator for different stopping positions and motion times. Simulations are achieved by using motion profiles. The performance of the motion profiles is evaluated by considering the reduction ratio of residual displacement and acceleration vibrations generated at the endpoint of the manipulator. RMS values of residual vibrations are calculated to determine the rate of residual vibration suppression. Reduction ratios are determined by considering the maximum vibration amplitudes as the reference RMS value. The effectiveness of the motion profiles is presented in comparison with the reduction rates. Simulation results obtained using both displacement and acceleration vibration responses are verified with experiments for all motion cases. Also, the modeling and analysis of the composite manipulator are verified by simulations and experiments with the SimMechanics-based modeling method, and the reliability of the proposed method is increased.
AtıfScopus8WoS8OpenAlex8İncele - MakaleYalnız künye2022Scopus SJRQ1Production and characterisation of goat milk powder made from sonicated whole milk concentrates
Sert, Durmuş; Mercan, Emin
In the present study, goat milk powder (GMP) was produced from sonicated whole milk concentrates for 0–60 min. The physicochemical, functional, and microbiological properties and powder flow behaviours of the GMP samples were determined. Sonication decreased firmness and consistency values of milk concentrate with the increased treatment time. L∗ value of the sonicated GMPs was higher than that of the control. The bulk density of samples was between 0.681 and 0.736 g cm−3, increased by sonication. However, sonication resulted in lower wettability, dispersibility, and foaming capacity. The D [3,2] value of GMPs ranged from 21.9 to 31.1 μm, increased by sonication. Sonication caused reduced cohesion and caking properties of GMPs compared with the control. Also, lower compaction levels at different flow rates were determined in the sonicated samples. In general, powder flow analyses showed that sonication improved GMP flow behaviour. Sonicated samples had reduced microbial load compared with the control.
AtıfScopus12WoS8OpenAlex11İncele - MakaleAçık Erişim2022Scopus SJRQ2Characterization of Essential Oil and Wastewater from Thymus nummularius M. Bieb. and Micromorphological Examination of Glandular Trichomes
Gerçek, Yusuf Can; Bayram, Sinan; Çelik, Saffet; Canlı, Deniz; Mavaldi, Muhammed Halid; Boztas, Kadir; Bastürk, Fatma Nur; Kırkıncı, Seran; Yesil, Yeter; Kösesakal, Taylan
This study aimed to determine the volatile profile by GC-MS and antimicrobial activity of the essential oil isolated from Thymus nummularius using the microwave-assisted hydrodistillation method and morphologically characterize the glandular trichomes in leaf samples. Obtained essential oil, as well as wastewater obtained during essential oil isolation, were chemically (polyphenolic compounds, organic acids, total phenolic content, total flavonoid content and antioxidant activity) characterized. As a result of GC-MS analysis of the essential oil, different ratios of essential oil components were identified, predominantly thymol (38.91%), linalool (13.12%) and geraniol (6.51%). The antimicrobial activity results showed that T. nummularius essential oil has a broad-spectrum inhibitory effect against all target microorganisms (bacteria and yeast-like fungi). Screening of 32 polyphenolic compounds and 52 organic acids in the wastewater was performed by LC-MS/MS and the major polyphenolic compound and organic acid were determined as caffeic acid (97316.85 µg/kg) and malic acid (6898.88 mg/kg), respectively. While the total phenolic and flavonoid content of the wastewater were 35.91 mg GA/g and 34.91 mg QE/g, respectively, the antioxidant activity results were obtained using the CUPRAC, CERAC and ABTS tests were 86.28 mg TE/g, 72.85 mg TE/g and 47.88 mg TE/g. These results support that the T. nummularius, an important production area in Turkey, can be used in different industrial areas due to its rich bioactive content. In addition, it can be said that wastewater is also considered a valuable source of bioactive substances.
AtıfScopus11WoS8OpenAlex11İncele - MakaleAçık Erişim2022Scopus SJRQ1Molecular Cloning, Expression and Characterisation of a Bacterial Myrosinase from Citrobacter Wye1
Cebeci, Fatma; Mayer, Melinda J.; Rossiter, John T.; Mithen, Richard; Narbad, Arjan
Glucosinolates are plant natural products which on degradation by myrosinases give rise to the beneficial bioactive isothiocyanates. Recently, a myrosinase activity was detected in a Citrobacter strain isolated from soil. This enzyme was purified enabling its amino acid sequence and gene sequence (cmyr) to be determined. In order to study this myrosinase it was necessary to establish an expression system that would enable future work such as a structural determination of the protein to be carried out. The myrosinase gene was amplified, cloned and expressed in Escherichia coli with a 6XHis-tag. The heterologous expression of cmyr enabled relatively large amounts of myrosinase to be produced (3.4 mg cmyr/100 ml culture). Myrosinase activity was determined by mixing substrate and enzyme and determining glucose release. Optimum pH and temperature were determined to be pH 6.0 and 25 °C for the Ni-NTA purified protein. The kinetic parameters of the purified myrosinase were determined using sinigrin as a substrate. Km and Vmax were estimated as 0.18 mM and 0.033 mmol/min/mg respectively for sinigrin under optimum conditions and compared to other kinetic data for myrosinases. The substrate specificity of myrosinase was determined having the highest affinity for sinigrin followed by glucoiberin, progoitrin, glucoerucin, glucoraphanin and glucotropaeolin.
AtıfScopus21WoS14OpenAlex16İncele - MakaleAçık Erişim2022Scopus SJRQ2On the plane receding contact between two functionally graded layers using computational, finite element and artificial neural network methods
Öner, Erdal; Şengül Şabano, Bahar; Uzun Yaylacı, Ecren; Adıyaman, Gökhan; Yaylacı, Murat; Birinci, Ahmet
The frictionless double receding contact problem for two functionally graded (FG) layers pressed by a uniformly distributed load is addressed in this paper. The gradation in the layers is assumed to follow an exponential variation through the height with constant Poisson's ratios. The lower layer rests on a homogeneous half-plane (HP). There is no adhesion between the FG layers or between the lower layer and the HP. The body forces of the FG layers and HP are ignored. First, the governing equations are reduced to a system of two singular integral equations with contact pressures and contact lengths as unknowns using Fourier transform techniques and boundary conditions. The integral equations are solved numerically using the Gauss-Chebyshev integration formula. Then, a parametric finite element analysis is performed using the augmented contact method. Finally, the problem was extended based on the multilayer perceptron (MLP), an artificial neural network used for different problem parameters. The effects of stiffness parameters, the normalized load length, the ratio of shear moduli, the ratio of FG layer heights to the normalized contact lengths, and normalized maximum contact pressures are explored. The results of finite element analysis and the MLP approach are used to validate the normalized maximum contact pressures and contact lengths obtained from an analytical method based on elasticity theory, and finally, good agreement between these three methods results is obtained. The obtained results could help in designing multibody indentation systems with FGMs.
AtıfScopus85WoS84OpenAlex48İncele - MakaleAçık Erişim2022Scopus SJRQ3Optimization of lactose derivative hetero-oligosaccharides production using whey as the acceptor molecule by an active glucansucrase
Kabli, Mohammad; İspirli, Hümeyra; Balubaid, Mohammed; Taylan, Osman; Yılmaz, Mustafa Tahsin; Dertli, Enes
Glucansucrases are capable of synthesis of distinct oligosaccharides using different acceptor molecules and in this study lactose derivative hetero-oligosaccharides were shown to be produced by an active glucansucrase in its acceptor reaction with sucrose and whey as the donor-acceptor molecules, respectively. Following the monitoring of the reaction products by TLC analysis, the effects of reaction parameters in terms of enzyme concentration, sucrose/whey ratio and reaction temperature on final oligosaccharide yields (OY) were optimized by Response Surface Methodology (RSM). Results indicated that increment of enzyme concentration and reaction temperature decreased the OY in a particular reaction time whereas the OY increased with the increment of sucrose/whey ratio in the acceptor reactions of glucansucrase E81 with whey as the acceptor molecule. A low level of glucansucrase E81 concentration was sufficient to obtain the highest OY in the tested conditions. These findings demonstrated the importance of the optimisation of the reaction parameters for the acceptor reactions of the glucansucrases.
AtıfScopus2WoS4OpenAlex6İncele - MakaleYalnız künye2022Scopus SJRQ2Lower bounds for blow-up time in a nonlinear parabolic problem with a gradient nonlinearity
Ayazoglu Mashiyev, Rabil; Ekincioglu, Ismail
In this article, we study the blow-up properties of solutions to a parabolic problem with a gradient nonlinearity under homogeneous Dirichlet boundary conditions. By constructing an auxiliary function and by modifying the first order differential inequality, we obtain lower bounds for the blow-up time of solutions in Lk(Ω ) (k> 1 ) norm and conditions which ensure that blow-up cannot occur.
- MakaleAçık Erişim2022Scopus SJRQ2In vitro digestibility and predicted glycemic index of commonly consumed some Turkish traditional foods
Koseoglu, Sabiha Zeynep Aydenk; Celikel, Seda
This study was planned to determine in vitro glycemic indices of some traditional foods frequently consumed by Turkish nation and to evaulate their effects on nutrition. Glycemic indices of roasted chickpea, Turkish bagel, tarhana, bulgur, Turkish delight, baklava, pişmaniye and kadayıf species; white bread was taken as reference (70) and analyzed in vitro by taking digestive system model. Glycemic index of Turkish bagels and bulgur was high (> 70), medium (55-70) of tarhana and low (<55) of roasted chickpea. There was a significant relationship between the hydrolysis indices of Turkish Delight and other sweet foods and also glycemic indices (p <0.05). Absorption rates of all foods increased and reached the highest level in parallel with their hydrolysis indices after 3 hours. Turkish delight had the highest RAG (glucose released from starch and sugars within 20 min incubation), while RAG and RDS (rapidly digestible starch) of the roasted chickpea were low. Chickpeas with the lowest glycemic index according to their digestibility and effects on blood glucose should be recommended by nutrition professionals to provide glycemic control and controlled consumption of the delight with the highest glycemic index.
AtıfScopus9WoS6OpenAlex9İncele - MakaleAçık Erişim2022Scopus SJRQ1Optimization of Asymmetric Bioreduction Conditions of 2-methyl-1-phenylpropan-1-one by Lactobacillus fermentum BY35 Using I-Optimal Design-Based Model
Aksuoğlu, Selmani; Özdemir, Akın; Serencam, Hüseyin; Dertli, Enes; Şahin, Engin
The bioreduction of prochiral ketones offers efficient access to chiral secondary alcohols, which are potentially beneficial precursors for producing many biologically active compounds and natural products. This bioreduction process can be affected by different parameters when whole-cell of biocatalysts such as Lactic Acid Bacteria strains are applied. In this context, this paper proposed an I-optimal design-based model to optimize culture parameters such as temperature, pH, incubation period, and agitation speed for asymmetric bioreduction of 2-methyl-1-phenylpropan-1-one (1) with Lactobacillus fermentum BY35 as a biocatalyst while achieving the highest conversion rate (cr) and enantiomeric excess (ee). The optimum settings of the four culture parameters and the cr and ee values were found using the proposed optimization model as follows: pH = 6.5, temperature = 25 °C, incubation period = 38.5 h, agitation speed = 200 rpm, the ee value = 98.78%, and the cr value = 98.92%. After the validation of the process, the cr and ee values were found to be > 99% and > 99%, respectively, while using the optimum operating conditions from the optimization model. Thus, the results of the optimization model are consistent with the results of the validation experiment. It is also noted that this paper is the first to optimize culture parameters using the proposed I-optimal design-based model for an asymmetric reduction.
AtıfScopus3WoS3OpenAlex3İncele - MakaleYalnız künye2022Scopus SJRQ3The role of Turkey in the world hazelnut production and exporting
Uzundumlu, Ahmet Semih; Kurtoğlu, Seval; Şerefoğlu, Coşkun; Algur, Zafer
The aim of this study is to estimate the future of the global hazelnut sector for 2019-2025 using the data of 1961-2018. ARIMA model was used to forecast hazelnut production and export quantity. Hirschman Herfindahl Index (HHI) and Concentration Ratios (CR) have been used to determine market status. According to HHI and CR, the world hazelnut market was oligopoly in 1961-2018 and the biggest player in this market was Turkey. Because Turkey was the largest manufacturer and marketer of hazelnut in the industry, 64% of the production and 67% of the exports of world hazelnut were provided by Turkey as the average in the period 2011-2018. Turkey thus determines the world price in hazelnut. According to the concentration ratio, CR1 will be 0.63 and 0.67 in the export and production; this means that about 63-67% of the world hazelnut production and export will have been provided by Turkey from 2019 to 2025. The number of countries producing, and exporting hazelnuts has risen from 13 to 32, and 9 to 58, respectively in the past fifty-eight years in the world. According to the findings of this study, it was forecasted that the competition degree of Turkey’s hazelnut export market will decrease during the period from 2019 to 2025. The results obtained from this study will help policymakers to monitor the way for hazelnut marketing in Turkey.
AtıfScopus20WoS16İncele - MakaleYalnız künye2022Scopus SJRQ2Bending analysis of two-directional functionally graded beams using trigonometric series functions
Turan, Muhittin
In the present paper, Navier’s method based on the first-order shear deformation theory for bending analysis of two-directional functionally graded beams subjected to various sets of boundary conditions is presented. In Navier's method, different trigonometric series functions are proposed for each boundary condition. The accuracy of these proposed functions was investigated and compared with the literature. It is also presented in a parametric study. The governing equations are derived according to Lagrange’s principle. The variation of the components of the beam material in the volume is defined by a power-law rule. The normalized maximum transverse deflections, the normalized axial and transverse shear stresses are obtained for various boundary conditions, gradation exponents (px, pz) in the x- and z-directions, and the slenderness (L/h). The trigonometric series functions used in this study give results that are quite compatible with the literature. In addition, the parametric study contributes to the literature.
AtıfScopus31WoS31OpenAlex27İncele - MakaleAçık Erişim2022Scopus SJRQ2Precipitation-hardening stainless steels: Potential use radiation shielding materials
Alım, Bünyamin; Özpolat, Özgür Fırat; Şakar, Erdem; Han, İbrahim; Arslan, İbrahim; Singh, V.P.; Demir, Lütfü
In this study, it was focused on the research of new materials with high attenuation efficiency that can be used as radiation shielding material due to the incapability of conventional materials. In accordance with this purpose, the radiation shielding capabilities of four different precipitation-hardening stainless steels (PH-SSs), which are symbolized 15-5PH, 15-7PH, 17-4PH and 17-7PH, were determined both experimentally and theoretically in a wide range of radiation energy. For experimental measurements, two different detectors (Si(Li) and Na(Tl)) and twenty-three different photon energies (from 22.1 to 1332.5 keV) emitted from seven different radionuclides were used in narrow-beam transmission geometry. Phy-X/PSD software were used for theoretical calculations. The theoretically calculated parameters were determined both in the photon energies emitted by the radionuclides used in the experiment and in the continuous energy range of 0.015–15 MeV. Furthermore, in order to make a remarkable assessment of the integration of PH-SSs to nuclear energy applications, the all results obtained have been compared with the corresponding values of Fe-based steel concretes (steel-scrap (SS) and steel-magnetite (SM)), which are widely used as conventional shield materials in nuclear power plants. Moreover, in order to choose the best material to be used in nuclear applications among the PH-SSs, the results were evaluated comparatively in terms of both the characteristics of the materials and the magnitude of the radiation shielding parameters. Consequently, it was concluded that the material with the best radiation shielding performance among the examined PH-SSs was 15-7PH and the radiation shielding performance ranking was generally in the form of 15-7PH ≥ 15-5PH > 17-4PH > 17-7PH > SM > SS. Due to both high attenuation efficiency and superior properties for radiation shielding, it was determined that the PH-SSs can be used as new shielding materials in nuclear applications.
AtıfScopus25WoS25OpenAlex27İncele - MakaleAçık Erişim2022Scopus SJRQ2The Investigation of COD Treatment and Energy Consumption of Urban Wastewater by a Continuous Electrocoagulation System
Dede Sağsöz, Yeşim; Yilmaz, Alper Erdem; Ekmekyapar Torun, Fatma; Kocadağistan, Beyhan; Kul, Sinan
In this study, electrochemical treatment of urban wastewater with electrical conductivity of 1000 µS cm-1 and chemical oxygen demand of 250 mg L-1 was investigated using the variables of initial pH value, current density and flow rate. Electrocoagulation was used, in which aluminum and stainless steel were selected, as the electrochemical treatment process. The electrocoagulation process was operated in continuous mode. The data obtained in experimental studies show that the best COD removal efficiency occurred in experiments where the initial pH value was 6. The increase in current density from 5 A to 15 A decreased the removal efficiency from 79 to 67%. The increase in flow rate under constant current density also reduced the efficiency of removal as expected. In experiments in which current density and flow rate were examined together, the increase in flow rate allowed the application of higher current densities. This situation led to considerable reductions in energy consumption values, even if the COD removal efficiency did not significantly increase. The high COD removal obtained with the use of high flow rate and high current density indicates that the electrocoagulation process can be used for high flow rate municipal wastewater treatment.
AtıfScopus6WoS5OpenAlex5İncele