Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Çolak, Murat(8)
- Bayram, Sinan(5)
- Öner, Erdal(5)
- Can, Zehra(4)
- Ecem Bayram, Nesrin(4)
- Kolaylı, Sevgi(4)
- Turan, Muhittin(4)
- Demirtaş, Betül(3)
- Dispinar, Derya(3)
- Erbayrak, Engin(3)
- Gumus, Beril Eker(3)
- Kamiloğlu, Aybike(3)
- Türker, Temel(3)
- Yanik, Yusuf(3)
- Yuncuoglu, Ercument Ugur(3)
- Özdemir, Akın(3)
- Şahin, Engin(3)
- Aymelek, Abdullah(2)
- Birinci, Ahmet(2)
- Dertli, Enes(2)
- Ergün, Mustafa(2)
- Eryılmaz Türkkan, Gökçen(2)
- Gerçek, Yusuf Can(2)
- Gul, Volkan(2)
- Gıdık, Betül(2)
- Kahraman, Yusuf(2)
- Kamiloglu, Aybike(2)
- Kara, Yakup(2)
- Keskin, Merve(2)
- Kul, S.(2)
- Malgaca, Levent(2)
- Nabiyev, Vasif(2)
- Oktay, Mine Gül(2)
- Sefaoglu, Firat(2)
- Turhal, Uğur(2)
- Uslu, Emin(2)
- Uyar, Mehmet(2)
- Uzun Yaylacı, Ecren(2)
- Yaylacı, Murat(2)
- Özkök, Aslı(2)
Yayınlar
- MakaleAçık Erişim2024Scopus SJRQ1Antioxidant activity and phenolic content of bee breads from different regions of Türkiye by chemometric analysis (PCA and HCA)
Can, Zehra; Gıdık, Betül; Kara, Yakup; Kolaylı, Sevgi
The objective of this study was to assess the antioxidant activity and phenolic compounds of bee bread samples obtained from various regions in Türkiye The goal was to characterize and classify 15 of bee bread samples based on their geographical origins. This investigation employed chemometric techniques, specifically principal component analysis (PCA) and a hierarchical clustering algorithm (HCA), for the inaugural comprehensive analysis of all data encompassing antioxidant activity and phenolic compounds in bee bread. The primary objective was to unveil potential clustering patterns among of bee bread samples based on their geographical origins. According to the results, the Total Phenolic Content (TPC) of bee bread samples ranged from 4.393 to 14.917 mg GAE/g dw, while the Total Flavonoid Content (TFC) exhibited variation within the range of 0.681 to 3.504 mg QE/g dw. p-OH benzoic and p-coumaric acids were detected in all samples. Other phenolic compounds were identified in different proportions among the bee bread samples. This study demonstrated the successful application of the PCA chemometric method to assess the antioxidant activity and phenolic compounds of bee bread samples from various regions of Türkiye. The results revealed effective clustering of the bee bread samples based on their geographical origins. Graphical Abstract: (Figure presented.)
AtıfScopus12WoS14OpenAlex16
İncele - MakaleAçık Erişim2024Scopus SJRQ1Feature selection with annealing for forecasting financial time series
Pabuccu, Hakan; Barbu, Adrian
Stock market and cryptocurrency forecasting is very important to investors as they aspire to achieve even the slightest improvement to their buy-or-hold strategies so that they may increase profitability. However, obtaining accurate and reliable predictions is challenging, noting that accuracy does not equate to reliability, especially when financial time-series forecasting is applied owing to its complex and chaotic tendencies. To mitigate this complexity, this study provides a comprehensive method for forecasting financial time series based on tactical input–output feature mapping techniques using machine learning (ML) models. During the prediction process, selecting the relevant indicators is vital to obtaining the desired results. In the financial field, limited attention has been paid to this problem with ML solutions. We investigate the use of feature selection with annealing (FSA) for the first time in this field, and we apply the least absolute shrinkage and selection operator (Lasso) method to select the features from more than 1000 candidates obtained from 26 technical classifiers with different periods and lags. Boruta (BOR) feature selection, a wrapper method, is used as a baseline for comparison. Logistic regression (LR), extreme gradient boosting (XGBoost), and long short-term memory are then applied to the selected features for forecasting purposes using 10 different financial datasets containing cryptocurrencies and stocks. The dependent variables consisted of daily logarithmic returns and trends. The mean-squared error for regression, area under the receiver operating characteristic curve, and classification accuracy were used to evaluate model performance, and the statistical significance of the forecasting results was tested using paired t-tests. Experiments indicate that the FSA algorithm increased the performance of ML models, regardless of problem type. The FSA hybrid models showed better performance and outperformed the other BOR models on seven of the 10 datasets for regression and classification. FSA-based models also outperformed Lasso-based models on six of the 10 datasets for regression and four of the 10 datasets for classification. None of the hybrid BOR models outperformed the hybrid FSA models. Lasso-based models, excluding the LR type, were comparable to the best models for six of the 10 datasets for classification. Detailed experimental analysis indicates that the proposed methodology can forecast returns and their movements efficiently and accurately, providing the field with a useful tool for investors.
AtıfScopus28WoS18OpenAlex32İncele - MakaleAçık Erişim2024Scopus SJRQ2Effects of Recycled Asphalt Material and Natural Pozzolan as Additives of Hot-Mix Asphalt: A Field Study
Yilmaz, Bahadır; Şentürk, Mehmet Akif
Using existing resources more efficiently and effectively becomes important currently. The question of how to make the best use of resources arises in the choice between constructing new roads and improving deteriorated existing roads. It is also important to reduce the amount of consumption and cost of materials. This has emerged the need to use waste materials by recycling and reusing. In this study, a new hot-mix asphalt (HMA) mixture was developed using recycled asphalt pavement (RAP), which was obtained by excavating the surface of a road at the end of its service life, together with a waste material namely natural pozzolan (NP). The final obtained mixture was used as a wear layer on an active highway. Core specimens were extracted from the paved layer for one year and subjected to dynamic and mechanical laboratory tests. Adding NP improved the resistance of the HMA mixture under heavy seasonal effects and traffic loads. In addition, NP increased the tensile strength, making the HMA mixture more resistant to deformation than control and RAP HMA mixtures. Dynamic creep test results showed that the control asphalt mixture had the most deformation and that the RAP mixture with NP had the least. According to the laboratory results, NP addition increased the stability value of the control mixture by 40%. Especially in cold seasons, the role of NP was more evident. In the performance tests that were applied on core samples taken from the field, ITS values for September increased by 98%, and the deformation values obtained as a result of the dynamic creep test decreased by 12%. In summary, adding NP to RAP HMA improves the performance of the pavement and the cost-effectiveness of the environmentally friendly use of RAP in HMA.
AtıfScopus1WoS1OpenAlex1İncele - MakaleYalnız künye2024Scopus SJRQ1Variations of natural frequencies of masonry minarets due to environmental effects
Yanik, Yusuf; Aymelek, Abdullah; Yildirim, Ömer; Demirtaş, Betül; Türker, Temel
It is very important to distinguish the reason of change in natural frequencies of structures either caused by a possible damage or environmental conditions (temperature and humidity). In this study, the changes in the dynamic properties of masonry and reinforced concrete minarets under environmental effects, such as temperature and humidity, were investigated. The masonry minarets of İskenderpaşa, Hacı Kasım, and Tavanlı Mosques and the reinforced concrete minarets of Karadeniz Technical University, Dilaveroğlu and Papatya Mosques in Trabzon were monitored by ambient vibration test method, and the relationship between natural frequencies and temperature and humidity was tried to be determined. For this purpose, the natural frequencies of these minarets were measured at certain intervals under different temperature and humidity conditions over a period of approximately 6 months. The vibration measurement system which was developed by our research team was used in the measurements. From the data collected by these measurements, the variation intervals of the natural frequencies (the smallest and the highest values), the percentages of change and their relations with temperature and humidity were revealed. This relationship was determined using linear–non-linear simple and multiple regression analyses. From this study, it was found that the natural frequencies change under environmental effects, such as temperature and humidity, and this rate of change was approximately 7%. There was moderate correlation in Tavanlı, Dilaveroğlu, and Papatya Minarets, and strong correlation in Hacı Kasım Minaret.
AtıfScopus16WoS17OpenAlex16İncele - MakaleYalnız künye2023Scopus SJRQ2Free vibration and buckling of functionally graded porous beams using analytical, finite element, and artificial neural network methods
Turan, Muhittin; Uzun Yaylacı, Ecren; Yaylacı, Murat
In this study, an analytical solution based on the first-order shear deformation theory was performed for free vibration and buckling analysis of functionally graded porous beams (FGM-P) subjected to various boundary conditions. Also, this problem is solved by using finite element (FEM) and artificial neural network (ANN) methods. Here a Ritz-based analytical solution is used, and different polynomial series functions are proposed for each boundary condition. Lagrange's principle was used while deriving the equations of motion. A power-law rule describes the variation of the beam's materials in volume. The normalized fundamental frequencies and critical buckling loads are obtained for various boundary conditions, power-law index (k), slenderness (L/h), porosity coefficient (e), and porosity distribution (FGM-P1, FGM-P2). The polynomial series functions used in this study were verified with the literature, and the numerical results obtained were compared with FEM and ANN. The results obtained are quite compatible with each other.
AtıfScopus140WoS136OpenAlex101İncele - MakaleAçık Erişim2023Scopus SJRQ1The effect of various industrial dust particles on the performance of photovoltaic panels in Turkey
Güngör, Okan; Kahveci, Hakan; Gökçe, H. Süleyman
The accumulation of dust is one of the main causes of power loss in photovoltaic (PV) farms, and the effect of dust particles’ size and chemistry on system performance is often overlooked. This study has focused on a comprehensive analysis of the effect of different dust particles collected from common industrial production facilities in Turkey on the performance of PV panels in the indoor laboratory environment. The collected dust samples were analyzed to determine the dust sample particles’ chemical properties, size, character, and topography. The data for dust samples at different weights with changes in maximum power point (MPP) of PV panel has been collected using the artificial solar irradiation source system. Thus, the mathematical correlations (R2≥0.965) between the PV panel Thevenin resistance (RTH), fill factor (FF), MPP, and pollution rate were obtained using these collected data and particle swarm optimization (PSO). According to the results of the obtained mathematical correlations, marble dust is 2.3, 3.4, and 4.2 times less polluting than cement, fly ash, and silica fume, respectively. Additionally, it was observed that smaller dust particles block more light than larger ones of the same weight and reduce MPP, FF while increasing the RTH.
AtıfScopus19WoS14OpenAlex21
İncele - MakaleYalnız künye2023Scopus SJRQ1Comparison of bioactive constituents by HPLC–DAD–ESI-MS and UFLC and in vitro antioxidant activities of blossom honey, bee pollen, and propolis
Saroğlu, Öznur; Ecem Bayram, Nesrin; Özçelik, Beraat
The aim of this study was to analyze the total phenolic content, phenolic profile, and antioxidant activity of honey, bee pollen, and propolis samples from Turkey's Black Sea Region. The total phenolic content of these bee products was found using Folin–Ciocalteu's method, and their antioxidant capacity was found using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and cupric ion reducing antioxidant capacity (CUPRAC) assays. Phenolic compounds of honey samples were characterized by high-performance liquid chromatography coupled to a photodiode array detector and mass spectrometer (HPLC–DAD–ESI-MS), while phenolic compounds of bee pollen and propolis samples were quantified ultra-fast liquid chromatography (UFLC). The total phenolic values for honey, bee pollen and propolis were 6.32–18.21 mg GAE/100 g, 547.64–769.4 mg GAE/100 gr, and 6096.1–11,564 mg GAE/100 gr, respectively. DPPH and CUPRAC values of honey, pollen and propolis were 11.05–21.38% and 0.38–1.48 µmol Trolox/g; 24.67–38.63% and 0.03–0.05 mmol Trolox/g; 11.81–34.12% and 0.47–0.89 mmol Trolox/g, respectively. About 30 different phenolic compounds were identified as quantitative. Our findings have shown that all bee products examined in the study are found to contain gallic acid, naringenin, and caffeic acid. In terms of total phenolic content and antioxidant activity, the bee product extracts were ranked as follows: propolis > bee pollen > honey. The high concentration of phenolic compounds in propolis explains its remarkable antioxidant effect.
AtıfScopus10WoS10OpenAlex10İncele - MakaleYalnız künye2023Scopus SJRQ1Nectar honey from Turkey: crystallization and physicochemical profile
Ecem Bayram, Nesrin
Honey is a traditional food used by humans due to many therapeutic properties. Turkey is in a good position for the production of bee products, and honey is the most popular bee product in the country. In this study, the aim was to evaluate the quality parameters of 40 honey samples based on physicochemical parameters and to gain information about speed of crystallization. For this purpose, moisture (%), fructose (%), glucose (%), fructose + glucose (F + G, %), fructose/glucose (F/G), glucose/moisture (G/M), and proline (mg/kg) contents were determined in honey samples and cluster analysis was performed. When the sugar profile of honey samples is examined, F + G was 61.63–78.03%, F/G was 0.99–1.25, moisture content was 14.9–19.1%, and proline content was 384.41–1271.56 mg/kg. These results comply with national standards. Honey samples tend to crystallize quickly when their crystallization properties are evaluated based on F/G and G/M ratios. Consequently, the quality of honey differs according to the region from which it is produced and it is natural for honey to crystallize.
AtıfScopus4WoS3OpenAlex6İncele - MakaleAçık Erişim2023Scopus SJRQ2Efficient production of acetone butanol ethanol from sole fresh and rotten potatoes by various Clostridium strains
Avcı, Ayşe; Kamiloğlu, Aybike; Dönmez, Sedat
This study aimed to evaluate rotten potato in the fermentation of acetone butanol ethanol (ABE). For this purpose, three strains, Clostridium acetobutylicum DSMZ 1731, Clostridium acetobutylicum DSMZ 6228, and Clostridium beijerinckii DSMZ 6422, were used and production experiments were performed in a simple media only composed of either fresh or rotten potato. Effects of potato concentration (100–400 g/L) and time (24–144 h) on the fermentation were determined using fresh potato. The highest ABE production was detected at 400 g/L potato concentration at the end of 96 h by all strains. Clostridium acetobutylicum DSMZ 6228 was the most efficient strain in producing ABE among the microorganisms tested. Total ABE productions by Clostridium acetobutylicum DSMZ 1731, Clostridium acetobutylicum DSMZ 6228, and Clostridium beijerinckii DSMZ 6422 at 400 g/L in 96 h were 12.3, 17.6, and 12.0 g/L, respectively. The majority of the products was butanol that made up ca. 66–67% of total ABE. Significant amounts of ABE were also produced with rotten potato which was compatible with the results obtained with fresh potato. They were determined as 11.5, 17.1, and 9.6 g/L with Clostridium acetobutylicum DSMZ 1731, Clostridium acetobutylicum DSMZ 6228, and Clostridium beijerinckii DSMZ 6422, respectively. The results showed that rotten potato could be a good candidate as substrate for ABE fermentation.
AtıfScopus18WoS16İncele - MakaleYalnız künye2023Scopus SJRQ2Optimization of microwave-assisted biosynthesis of silver nanoparticle with tarragon extract
Altuncu, Fatma Kübra; Kamiloğlu, Aybike
Response surface method was used to optimize microwave-assisted silver nanoparticle production with tarragon extract. As a result of the optimization study, tarragon silver nanoparticles (TAgNPs) were produced from 43 conditions with a degree of desirability of 1, with a processing time of 5.25 min, AgNO3 concentration of 9.89 mM, and tarragon extract concentration of 14.80%. Among the variable parameters, AgNO3 concentration affected TAgNP synthesis depending on processing time and tarragon extract concentration; tarragon extract concentration was found to significantly affect nanoparticle formation. TAgNP produced under optimum conditions was found to be crystalline, with a spherical surface morphology and an average particle size of 16.56 nm, with scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction diffractometry (XRD) analyses. TAgNPs showed inhibitory effect for Escherichia coli BC 1402, Bacillus cereus BC 6830, Salmonella typhimurium RSSK 95091, Yersinia enterocolitica ATCC 27729, and Staphylococcus aureus ATCC 25923 microorganisms. The minimum inhibition concentrations were 10 µg/mL for B. cereus BC 6830, 50 µg/mL for E. coli BC 1402, S. typhimurium RSSK 95091, and Y. enterocolitica ATCC 27729, and 25 µg/mL for S. aureus ATCC 25923.
AtıfScopus2WoS2OpenAlex2İncele - MakaleAçık Erişim2023Scopus SJRQ3Comparison of Phenolic Profile and Antioxidant Properties of Pulp and Seeds of Two Different Grapes Types (Vitis vinifera L. and Vitis labrusca L.) Grown in Anatolia: The Amount of Resveratrol of Grape Samples
Kavgacı, Merve; Yukunc, Gulsah Okumus; Keskin, Merve; Can, Zehra; Kolaylı, Sevgi
Background: Grape is the most widely cultivated fruit all over the World and it is both food and a good source of antioxidants. The fruit is rich in phytochemicals and its seed is especially a source for resveratrol, a stilbene that shows health promoting effect. Objective: In this study, phenolic profile and antioxidant properties of eight grape cultivars with two species cultivated in Turkey were compared. Isabella, Razaki, Alphonse Lavalleé, Red Globe and Emir cultivars were used. Methods: Total phenolic substance (TPS), total flavonoid substance (TFS), total antioxidant capacity (FRAP) and phenolic compositions of the pulp and the seeds were determined. Phenolic composition of grapes were found by using HPLC-UV. Results: The results showed that total phenolic substances and total antioxidant capacities were richer in the seeds than in the pulps. Catechin and epicatechin are major phenolic compounds in the grape seeds, and chrysin, pinocembrin, resveratrol, luteolin and caffeic acid phenethyl ester (CAPE) were detected in the pulp as major. Resveratrol varied from 4.50 to 101.89 mg/100 g, while was equally in both the seed and pulp. It was found that all grape samples were rich in phenolic compounds and had antioxidant activity. Conclusion: It was clear that antioxidant capacity and phenolic profile of samples changes according to grape species and cultivars.
AtıfScopus11WoS7OpenAlex10İncele - MakaleAçık Erişim2023Scopus SJRQ2Experimental study of adhesively bonded joints with dissimilar composite laminates under different loading rates and ambient temperatures
Erbayrak, Engin; Gumus, Beril Eker; Yuncuoglu, Ercument Ugur
An experimental study of the single-lap joints at different loading rates and ambient temperatures was investigated. In the experiment, a single lap joint was formed using plain woven glass fiber reinforced epoxy (GFRE) laminates, plain woven aramid fiber reinforced laminates (AFRE), and Araldite 138 M / HV998 epoxy adhesive. The composite laminates were produced using Vacuum-Assisted Resin Transfer Molding (VARTM) process. Adhesively bonded joints were created using similar and dissimilar adherends. Experiments were carried out under different loading rates (1 mm/min, 10 mm/min, 50 mm/min, 100 mm/min) and ambient temperatures (23°C,60°C,100°C). Stress–strain graphs were obtained for each experimental condition. It is seen that the maximum stress values increase as the loading rate increases in all single lap joints at all different temperatures. However, in all single lap joints, at all different loading rates, the maximum stress value decreases as the ambient temperature increases.
AtıfScopus7WoS7OpenAlex7İncele - MakaleAçık Erişim2023Scopus SJRQ1Palynological, chemical, antimicrobial, and enzyme inhibition properties of Cannabis sativa L. propolis
Özkök, Aslı; Karlıdağ, Semiramis; Keskin, Merve; Bayram, Sinan; Keskin, Şaban; Karabulut, Ercan; Çiçek, Fevzi; Yılmaz, İsmet
In this study, both chemical characterization and biological activities of propolis samples obtained from Cannabis sativa L. (cannabis, hemp, marijuana) isolated colonies (research group) and obtained from colonies at a distance where the bee cannot fly to the isolation area (control group) were determined. Palynological analyses of propolis samples obtained from the research and control group colonies were made and the botanical origin of the cannabis plant and other plants in the research area and the plants in the control group were determined. Bioactive component analysis of propolis extracts was determined by the GC–MS technique. The inhibition effect of propolis samples on some enzymes of medical importance and their antimicrobial effects against many pathogenic microorganisms were also investigated. Palynological analyses showed that honey bees prefer cannabis plants (11.11%) when collecting propolis, and the dry matter percentage (94.6 ± 1.8%), balsam (46.2 ± 5.2%), and wax content (4.8 ± 0.5%), total phenolic (26.44 ± 1.08 mg GAE/mL) and total flavonoid (2.03 ± 0.11 mg QE/mL) content and antioxidant capacity (88.16 ± 2.27 μM FeSO4·7H2O/mL−1) of the research group propolis samples containing hemp were found to be higher than the control group. Also, it was determined that the research group propolis sample contains cannabinoid derivatives (cannabidivarinic acid, 0.29%; delta (1)-tetrahydrocannabinolic acid, 0.59%; cannabidiolic acid, 0.48%), which are active compounds of the cannabis plant. Also, a high inhibition effect was detected on some enzymes of medical importance in propolis samples obtained from cannabis group colonies. In addition, the research group propolis samples also showed a high antimicrobial effect against many pathogenic microorganisms.
AtıfScopus5WoS5OpenAlex4İncele - 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 - 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 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 - Kitap BölümüYalnız künye2022Scopus SJRQ4Initial Responses to COVID-19 Pandemic in Turkey: General, Financial, and Legal Measures
Göçoğlu, Volkan; Şengün, Hayriye
The COVID-19 pandemic started in Wuhan, China, and spread to almost all over the world in four months. As pandemic cases began to be detected and increased in countries, governments have started to pursue various policies such as closing the city and country borders, social distance practices, the prohibition of going out, and creating herd immunity. Especially with the closure measures implemented, the countries’ financial systems have been adversely affected, and many sectors have suffered losses. On the other hand, the provision of public services in countries has become more complex. Therefore, countries have taken several measures to maintain their public services without interruption. Legal services are one of the essential services affected by this situation. This study deals with the general, financial and legal measures that Turkey has adopted to combat against COVID-19 pandemic. As a result of the study, while the functional features that stand out in the measures are presented, some suggestions are made for a better crisis management.
- MakaleAçık Erişim2022Scopus SJRQ1Optimization of Biocatalytic Production of Enantiopure (S)-1-(4-Methoxyphenyl) Ethanol with Lactobacillus senmaizuke Using the Box–Behnken Design-Based Model
Kavi, Mervenur; Özdemir, Akın; Dertli, Enes; Şahin, Engin
Enantiomerically pure (S)-1-(4-methoxyphenyl) ethanol is a significant molecule for the production of various drug intermediates. (S)-1-(4-methoxyphenyl) ethanol was synthesized from 4-methoxyacetophenone using Lactobacillus senmaizuke as a biocatalyst. In addition, optimization of experimental conditions is important to analyze the role of culture parameters for catalytic bioreduction reactions. For this particular purpose, the experimental conditions of pH, incubation period, temperature, and agitation speed were investigated with the Box–Behnken experimental design-based proposed optimization model. (S)-1-(4-methoxyphenyl) ethanol, which can be used for the synthesis of antihistamines, including diphenhydramine hydrochloride and loratadine cycloalkyl [b] indoles that have the treatment function for an allergic response, was obtained in > 99% conversion, > 99% enantiomeric excess and 96% yield with whole cells of L. senmaizukei at this optimization conditions: pH = 5.80, the temperature = 29 °C, incubation period = 50 h, and agitation speed = 155 rpm. The bioreduction of 4-methoxyacetophenone efficiency was importantly affected by the quadratic and linear effects of experimental design parameters. Besides, the results demonstrate the importance of design parameters for catalytic bioreduction reactions. It is also concluded that the results show the effectiveness of the Box–Behnken experimental design-based proposed model to obtain optimum operating conditions of design parameters for catalytic bioreduction reactions.
AtıfScopus4WoS4OpenAlex4İncele - MakaleYalnız künye2022Scopus SJRQ2Organic acids and their derivatives: minor components of bee pollen, bee bread, royal jelly and bee venom
Çelik, Saffet; Gerçek, Yusuf Can; Özkök, Aslı; Ecem Bayram, Nesrin
This study aimed to determine the organic acid profiles of bee products such as royal jelly, bee venom, bee pollen and bee bread, as well as to verify the method employed in the study. For this purpose, royal jelly, bee venom, bee pollen and bee bread samples were obtained from different locations, and 55 individual organic acids were determined using the liquid chromatography technique coupled with tandem mass spectrometry (LC–MS/MS), and method verification was carried out. Moreover, principal component and hierarchical cluster analyses were performed to compare the organic acid content of bee products and evaluate the overall variation. According to the results, the order of the total organic acid profiles was determined as bee venom (4141 mg/kg-6260 mg/kg) > bee bread (736–990 mg/kg) > bee pollen (837–1503 mg/kg) > royal jelly (192–1947 mg/kg). Although citric acid (423–41,519 mg/kg) was dominantly detected in samples among the organic acids screened. It is thought that the results obtained will contribute to scientific studies carried out to determine the authenticity of bee products and their standardization.
AtıfScopus24WoS21OpenAlex26İncele - MakaleYalnız künye2022Scopus SJRQ3Optimization of Ultrasound Extraction of Phenolic Compounds from Tarragon (Artemisia dracunculus L.) Using Box–Behnken Design
Kutlu, Naciye; Kamiloglu, Aybike; Elbir, Tugba
In this study, ultrasound extraction of bioactive compounds from tarragon was examined as a sustainable technology. Pure water, which is a green solvent, was used as solvent. Box–Behnken was used in the experimental design, and ultrasonic power, extraction time and solvent-to-sample ratio were determined to be independent variables. The physicochemical properties were determined by physical (color, pH, Brix) and chemical analyses (antioxidant activity, total flavonoid and total phenolic compound (TPC)) in the extracts obtained under different conditions. Optimum conditions were found to be 73.9% ultrasonic power, 43.2 min sonication time and 10 mL/g solvent-to-sample ratio. The composite desirability (R2) of optimum conditions was 99.3% after optimization. Since high efficiency was obtained in a short time with ultrasound extraction, it was found to be quite good in terms of energy savings. That is, the highest TPC was obtained with a sonication time of 45 min with this method, while similar TPC in the control group (maceration) was obtained in 24 h. In the optimum conditions, extraction with other green solvents (ethanol and deep eutectic solvent—DES) was carried out and bioactive compound yields were compared. For different solvents compared under optimum conditions, ethanol gave higher yields in terms of TPC, while higher yields were obtained in samples using water as solvent for some antioxidant activity values. The results obtained with DES were not as high as expected, and this resulted in the conclusion that a hydrogen bond donor is not suitable for obtaining bioactive compounds from tarragon.
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