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- MakaleYalnız künye2021Scopus SJRQ2Vitamin, mineral, polyphenol, amino acid profile of bee pollen from Rhododendron ponticum (source of “mad honey”): nutritional and palynological approach
Ecem Bayram, Nesrin
In this study, it was aimed to characterize the pollen collected by bees from the Rhododenron ponticum plant, which is the source of mad honey, in terms of some parameters. In the first stage, the botanical origin of the sample was confirmed by palynological analysis supported by light microscopic images. Then, the chemical profile of Rhododenron ponticum bee pollen was examined in terms of 31 elements, 42 amino acids, 33 phenolics and vitamins A, B1, B2, B5, B6, B7, B12, C, E, K1 and K2. The total individual phenolic compound content of Rhododendron ponticum bee pollen was determined as 11928.23 µg/100 g, total element content as 13997.75 mg/kg, total free amino acid content as 149466.11 µg/g and total vitamin content as 20509.37 µg/100 g. In addition, it was characterized by a low content of vitamin A (retinol), B7, B12, K2, as well as a deficiency of vitamin K1. As a result of analysis with LC-MS-MS, it was found that it contains L-asparagine and myricetin in a significantly higher concentration compared to other amino acids and phenolic compounds. However, the presence of phenolic compounds (myricetin, epicatechin, tyrosol etc.) and amino acids (L-asparagine, gamma-aminobutyric acid, L- Tryptophan etc.) with significant biological activity indicates that this product is a bee product with high medicinal properties. Moreover, the significant presence of Mg, P, Fe and Ca, high K/Na ratio, vitamin C, B2, B5 and B6 content makes bee pollen collected from Rhododendron ponticum plant attractive for diets.
AtıfScopus36WoS27OpenAlex36
İncele - MakaleAçık Erişim2022Investigation of ball milling effect on superconducting properties of oleic acid added bulk MgB2 superconductors produced by two different methods; [İki farklı metot ile üretilen oleik asit katkılı külçe MgB2 süperiletkenlerin süperiletkenlik özellikleri üzerine bilyeli öğütme etkisinin araştırılması]
Erdem, Özge
The effect of ball milling on the microstructure and some superconducting parameters such as flux pinning force (Fp) and critical current density (Jc) of the oleic acid (C18H34O2) added MgB2 bulk samples produced by two different methods, was analysed in this article. In the first method, ball milling was applied to the samples produced by using boron (B) powders coated with carbon (C) released from oleic acid. In the second method, oleic acid was mixed with magnesium (Mg) and B powders at the same time and then the same ball milling process used in the first method was applied to the powder mixture. The structural, magnetic and electrical properties of the produced samples were analysed. The results showed that ball milling process enhances the homogeneity of the structure, decreases the grain size and improves the grain connectivity of MgB2. Also, C substitution into MgB2 lattice resulting in an increase in electron scattering and disorders, enhances after ball milling process. It supplies a significant increase in Jc at high fields and causes a slightly decrease in transition temperature (Tc), especially for the samples produced by using the first method. Because the first method supports the ball milling effect on the homogenous dispersion of oleic acid addition in the MgB2 structure and the C entrance to MgB2 lattice, acting as pinning centres, the best Jc and Fp values at high fields was obtained for the produced samples with second method.
AtıfScopus3OpenAlex1
İncele - MakaleAçık Erişim2020THERMAL ANALYSIS OF LONGITUDINAL A POROUS FIN WITH TEMPERATURE-DEPENDENT INTERNAL HEAT GENERATION USING THE VARIATION OF PARAMETERS METHOD
Güngör, Osman; Arslantürk, Cihat
. The present study investigates the thermal performance of longitudinal a porous fin with temperature-dependent internal heat generation. The Darcy model is utilized to obtain the differential form of the governing equation that solves the nonlinear temperature distribution equation using the method of variation of parameters. Although this method is applied to solve both linear and nonlinear differential equations, there exist rare applications of this method to solve nonlinear heat transfer problems. In the present study, we applied the method to estimate the thermal analysis of the porous fin exposed to convection. The heat generation is assumed as a function of temperature. The effects of the convection parameter Nc, internal heat generation ε, porosity Sn and generation number G parameter on the dimensionless temperature distribution are discussed in detail. The accuracy of the variation of parameters method is verified through comparison with homotopy perturbation method and the Matlab bvp4c solver (NUM). The results have disclosed that the variation of parameters method can be used as a very effective and practical approach for further studies of the porous medium.
AtıfOpenAlex1İncele - MakaleYalnız künye2020Scopus SJRQ1Characterisation of physicochemical, microbiological, thermal, oxidation properties and fatty acid composition of butter produced from thermosonicated cream
Sert, Durmuş; Mercan, Emin
The effects of thermosonication of cream on physicochemical, microbiological, thermal, oxidation properties and fatty acid composition of butter were determined. Butter samples were produced from cream thermosonicated (TS) for 5, 10, or 15 min and from raw (R) and pasteurised (P) cream as controls. Thermosonication decreased moisture content, water activity, and pH of samples when compared with control groups. Mean particle size (D [3.2]) values of TS samples were lower than the R and P samples. Thermosonication improved spreadability compared with that of butter from pasteurised cream. Oxidative stability (induction time) of TS samples was lower than R, but higher than P. Two melting peaks were determined; in all samples, the Tonset of the first peak ranged from 11.39 to 11.93 °C, and the Tpeak was between 14.01 and 14.14 °C. Thermosonication significantly reduced total bacteria count and can improve spreadability, oxidative stability, and microbial safety of butter samples.
AtıfScopus27WoS22OpenAlex26İncele - MakaleYalnız künye2021Scopus SJRQ1The effects of Cephalaria syriaca flour on physical, rheological and textural properties of sunn pest (Eurygaster integriceps) damaged wheat dough and bread
Başar, Şule; Karaoğlu, Mehmet Murat
The aim of this study was to investigate the effects of Cephalaria syriaca flour (CSF; 0.5, 1.0 and 1.5%) on the physical, textural and rheological characteristics of dough and bread obtained from sunn pest-damaged wheat (SPDW; 5, 10 and 15%). An increased CSF level significantly decreased the stickiness and volume loss values of dough and the firmness and chewiness values of bread for all SPDW levels. The dough stickiness and bread firmness values were considerably increased by the addition of SPDW at the 15% level (1.05 N and 29.76 N), whereas these values were reduced by the addition of 1.5% CSF (0.6439 N and 22.56 N). In general, the stress relaxation, gas retention and gluten extensibility parameters of dough; and the specific volume, colour, cohesiveness, springiness and resilience values of bread significantly increased depending on the increasing level of CSF. Especially, the 1.5% CSF level significantly improved the quality of the dough and breads. The results of the present study revealed that CSF addition to SPDW flour positively affected the stickiness, gas retention and stress relaxation of dough and the specific volume and instrumental textural properties of bread.
AtıfScopus13WoS10İncele - MakaleAçık Erişim2022Scopus SJRQ2PRE-SERVICE SCIENCE AND COMPUTER TEACHERS’ VIEWS ON TEACHING PRACTICE COURSES
Bulut, Ayhan; Kaban, Abdullatif; Bilen, Ömer
The Teaching Practice course taught in Education Faculties gives pre-service teachers real experience before starting the profession. This study aims to examine the teaching practice courses in the undergraduate programs of education faculties by the views of pre-service science and computer teachers. 50 4th grade students, 25 from the science education department and 25 from the computer and instructional technology education department, participated in the study. Within the scope of the study, the data were collected through online interviews of approximately 30 minutes with the participants, and content analysis was made. According to the findings, pre-service teachers believe that teaching practice courses are insufficient to ensure active participation in lessons in terms of learning gains and content and that they lack a flexible structure that allows them to participate in classes at various grade levels. They also stated that the teaching practice course includes result-oriented measurement and evaluation activities. However, they underlined that the semesters and credits allocated to undergraduate teaching practice courses are insufficient. Furthermore, throughout the process, pre-service teachers reported some communication and coordination issues in the teaching practice course. They suggested that every university with an education faculty should open practice schools that include all levels of compulsory education to overcome the challenges encountered during the process.
AtıfScopus1WoS1İncele - MakaleAçık Erişim2020Scopus SJRQ3Technological properties of autochthonous Lactobacillus plantarum strains isolated from sucuk (Turkish dry-fermented sausage)
Kamiloğlu, Aybike; Kaban, Güzin; Kaya, Mükerrem
Purpose: Five Lactobacillus strains isolated from sucuk (Turkish dry-fermented sausage) were studied for their genetic and technological properties. Methods: For genotypic identification, strains 16S rRNA gene sequences were used. To determine the antimicrobial activity of strains, seven foodborne pathogens were tested. Strains technological properties were characterized. Results: These strains were identified as Lactobacillus plantarum by 16S rRNA gene sequence analysis and the phylogenetic tree obtained by neighbor-joining method allowed grouping of these strains into three subgroups. L. plantarum strains showed antagonistic activities against Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, and Micrococcus luteus strains. PCR assay, using specific primers, showed the presence of bacteriocin (plantaricin) encoding genes in all L. plantarum strains tested. Antimicrobial metabolite production of these strains started at log phase and reached the maximum level at the end of the stationary phase. Regarding their technological properties, better growth was observed at 25 °C compared with 15 °C and 45 °C. The isolates which grown well within the pH scale pH 4.5–6.5 range additionally showed a decent growth at 6.5% salt concentration. It has been found that strains do not exhibit lipolytic and proteolytic activities nor have lysine, ornithine, and arginine decarboxylase activity. On the other hand, one strain showed weak nitrate reductase activity, and four strains produced acetoin from glucose. In addition, all strains were DL-lactic acid producers. Consequently, L. plantarum strains isolated exhibited some biochemical properties required for a starter culture in sucuk and similar products. Conclusions: All identified strains may be a protective culture in the production of fermented meat products. In particular, L. plantarum S51 was distinguished from other isolates due to the inability to form acetoin from glucose. Further work will be needed to characterize L. plantarum strains as starter culture.
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İncele - MakaleAçık Erişim2022Scopus SJRQ3Comparison of Serum Adropin Levels in Patients with Diabetes Mellitus, COVID-19, and COVID-19 with Diabetes Mellitus
Aydın, Pelin; Karabulut Uzunçakmak, Sevgi; Tör, İbrahim Hakkı; Bilen, Arzu; Özden, Ayşe
Objective: In the present study, the relationship between a poor prognosis and adropin levels in diabetic patients with coronavirus disease 2019 was investigated by measuring serum adropin levels and levels of D-dimer, C-reactive protein, and ferritin, which are considered prognostic factors for coronavirus disease 2019. Materials and Methods: Hundred volunteer participants treated in the Erzurum Regional Training and Research Hospital were included in this study. Serum adropin levels were measured by enzyme-linked immunosorbent assay. The relationship between serum adropin level and C-reactive protein, ferritin, and D-dimer levels was analyzed by correlation analysis. Results: The participants’ serum adropin levels differed between the groups (P =.0007). The control group had the highest adropin levels among groups. The lowest adropin levels were in the COVID + diabetes mellitus group. Adropin levels of diabetes mellitus, COVID, and diabetes mellitus + COVID groups were significantly decreased when compared to the control (P <.05). There was a significant negative correlation between adropin and C-reactive protein, D-dimer, and ferritin. Conclusion: Adropin can be used as an auxiliary biomarker, a prognostic factor in the early management of coronavirus disease 2019 patients with diabetes mellitus. We think that our study will guide future studies conducted in this field.
AtıfScopus9WoS10OpenAlex13TR Dizin3İncele - MakaleYalnız künye2020Scopus SJRQ1Impact of glucan type exopolysaccharide (EPS) production on technological characteristics of sourdough bread
İspirli, Hümeyra; Özmen, D.; Yılmaz, Mustafa Tahsin; Sağdıç, O.; Dertli, Enes
In this study, technological role of α-glucan with (α1-3) and (α1-6) glycosidic linkages produced by Lactobacillus reuteri E81 on sourdough rheology and bread texture was investigated. To achieve this, a glucan deficient ΔgtfA mutant was produced by the deletion of the glucansucrase gene from strain E81. By comparison of glucan-positive and glucan-negative strains for rheological properties of sourdough revealed that in situ α-glucan production resulted in higher elasticity in sourdough. However, no additional effect of in situ glucan on textural characteristics of bread was observed although addition of glucan ex situ at 0.09% level significantly decreased bread hardness. Scanning Electron Microscopy (SEM) images of lyophilized sourdoughs confirmed association of glucan and starch granules forming a film like structure in sourdough.
AtıfScopus71WoS58OpenAlex67İncele - MakaleYalnız künye2021Scopus SJRQ2Double-exponential current-voltage (I-V) behavior of bilayer graphene-based Schottky diode
Kutluoǧlu, Esra Efil; Orhan, Elif Oz; Tataroǧlu, Adem; Bayram, Ozkan
Researches on layered materials such as graphene have attracted lots of attention recently. It has been shown that these materials have make a junction with many semiconductor materials that behave like Schottky diodes and have rectifying characteristics. The comprehension of its fabrication process and properties are a critical need toward graphene-based integrated electronics. The purpose of this study is to find out the current-voltage (I-V) performance of Bilayer Graphene (BLGr) based heterostructure fabricated on Al2O3/p-Si, and the effect of BLGr on diode parameters. Graphene has been grown on copper (Cu) foil by Chemical Vapor Deposition (CVD) method and transferred onto Al2O3/p-Si by using the polymethyl methacrylate (PMMA) wet transfer method. Raman analysis has been performed to obtain supportive information about CVD synthesized graphene film. The I-V plot of the diode exhibited two linear regions named Region 1 (0.08-0.19 V) and Region 2 (0.21-0.40 V). The double-exponential I-V behavior of the diode has been analyzed. The diode characteristics such as barrier height (ΦB0), series resistance (Rs), and ideality factor (n) have been calculated by using thermionic emission (TE), Norde, and Cheung methods. Especially, the values of the barrier height were compared with one another. It was found that they are in good agreement. Additionally, current conduction mechanisms of the diode were investigated using the forward bias ln(I) versus ln (V) plot. At lower and higher forward bias regions, the conduction mechanisms were determined as ohmic behavior and trap charge limiting current mechanism (TCLC), respectively.
AtıfScopus3WoS3OpenAlex4İncele - MakaleYalnız künye2021Scopus SJRQ1Frictionless contact mechanics of an orthotropic coating/isotropic substrate system
Öner, Erdal
This study has been performed to investigate the receding contact problem of a homogeneous orthotropic coating that is not bonded to a homogeneous isotropic substrate without any interfacial defects. The isotropic substrate is supported on a Winkler foundation. The problem is solved assuming that the contact between the rigid punch and orthotropic coating, and that between the orthotropic coating and isotropic substrate, are frictionless. Additionally, the effect of the body forces is neglected, and only compressive normal tractions can be transmitted through the interfaces. The contact analysis of the orthotropic coating, which is subjected to a contact load using a rigid cylindrical punch, is performed under plane strain conditions. The governing equations are analytically found using the theory of elasticity and Fourier integral transformation techniques. Subsequently, the governing equations are reduced to a system of two singular equations, wherein the unknowns are the contact stresses and contact widths. To numerically solve the resulting singular integral equations, Gauss-Chebyshev integration formulas are employed. It is analyzed the influence of the following parameters on the contact stresses and contact widths: orthotropic-material properties, punch radius, load ratio, Winkler foundation stiffness.
AtıfScopus26WoS26OpenAlex10İncele - MakaleYalnız künye2021Scopus SJRQ1Investigation of continuous and discontinuous contact cases in the contact mechanics of graded materials using analytical method and FEM
Yaylacı, Murat; Adıyaman, Gökhan; Öner, Erdal; Birinci, Ahmet
The aim of this paper was to examine the continuous and discontinuous contact problems between the functionally graded (FG) layer pressed with a uniformly distributed load and homogeneous half plane using an analytical method and FEM. The FG layer is made of non-homogeneous material with an isotropic stress–strain law with exponentially varying properties. It is assumed that the contact at the FG layer-half plane interface is frictionless, and only the normal tractions can be transmitted along the contacted regions. The body force of the FG layer is considered in the study. The FG layer was positioned on the homogeneous half plane without any bonds. Thus, if the external load was smaller than a certain critical value, the contact between the FG layer and half plane would be continuous. However, when the external load exceeded the critical value, there was a separation between the FG layer and half plane on the finite region, as discontinuous contact. Therefore, there have been some steps taken in this study. Firstly, an analytical solution for continuous and discontinuous contact cases of the problem has been realized using the theory of elasticity and Fourier integral transform techniques. Then, the problem modeled and two-dimensional analysis was carried out by using ANSYS package program based on FEM. Numerical results for initial separation distance and contact stress distributions between the FG layer and homogeneous half plane for continuous contact case; the start and end points of separation and contact stress distributions between the FG layer and homogeneous half plane for discontinuous contact case were provided for various dimensionless quantities including material inhomogeneity, distributed load width, the shear module ratio and load factor for both methods. The results obtained using FEM were compared with the results found using analytical formulation. It was found that the results obtained from analytical formulation were in perfect agreement with the FEM study.
AtıfScopus78WoS78OpenAlex21İncele - MakaleAçık Erişim2020Scopus SJRQ1Gamma ray and neutron shielding characteristics of polypropylene fiber-reinforced heavyweight concrete exposed to high temperatures
Demir, İ.; Gümüş, M.; Gökçe, H.S.
The residual properties of shielding structures need to be redefined after exposure to elevated temperatures due to their probable radiological hazards on biodiversity. In this study, the effect of high temperatures on mechanical, gamma ray and neutron attenuation characteristics was determined for limestone, barite and siderite concrete shields reinforced with polypropylene fiber. The increase in temperature up to 600 °C reduced the ultrasonic pulse velocity and compressive strength values of these shields by 59% and 62%, respectively. A good linear correlation (R2 ≥ 0.97) was found between these values. While the gamma ray linear attenuation coefficients increased by 9% for barite concrete, and reduced by 15% for normal concrete and by 17% for siderite concrete at 600 °C, trivial fluctuations (from −1% to +7%) were observed at 300 °C. The neutron attenuation factors of these shields gradually reduced up to 31% with the increase of temperature. The performance of siderite concrete was found to be slightly better than that of barite concrete in terms of strength and neutron shielding characteristics. With the satisfactory linear attenuation coefficients at all energy levels of gamma rays, barite concrete seems to be the most suitable concrete type under high temperature risks.
AtıfScopus142WoS132OpenAlex150İncele - MakaleAçık Erişim2021Scopus SJRQ2Production of bread from doughs composed of high-pressure homogenisation treated flour slurries: effects on physicochemical, crumb grain and textural characteristics
Sert, Durmuş; Mercan, Emin; Tongur, Aymelek; Kara, Ümmügülsüm
This study aimed to investigate the physicochemical and textural characteristics of bread produced from doughs composed of high-pressure homogenization (HPH) treated flour slurries. For this purpose, bread samples were produced from doughs composed of HPH treated flour slurries at 0 (control), 20, 30, 50, and 70 MPa. HPH treatment resulted in decreased particle size with more uniformity in flour slurries. A monomodal particle size distribution was determined in slurries. HPH obtained higher firmness, consistency, and cohesivity in slurries. In bread samples, HPH increased yellowness and lightness values. The bread samples prepared from HPH treatment had 1.09–1.25 times higher specific volumes than the control sample. HPH treatment provided decreased hardness and increased cohesiveness and springiness values. Image analysis results showed HPH treatment decreased total cell count, whereas increased mean cell area of bread samples. The findings revealed that HPH treatment results in higher quality bread compared to control.
AtıfScopus5WoS5OpenAlex6İncele - MakaleAçık Erişim2020Scopus SJRQ1Synthesis and characterisation of alternan-stabilised silver nanoparticles and determination of their antibacterial and antifungal activities against foodborne pathogens and fungi
Yilmaz, Mustafa Tahsin; İspirli, Hümeyra; Taylan, Osman; Dertli, Enes
In this study, alternan isolated from Lactobacillus reuteri E81 was used as the stabilising agent to produce alternan-stabilised silver nanoparticles (AgNPs-Alt) and AgNPs-Alt were characterized and their antibacterial and antifungal activities were tested. The formation and the stability of AgNPs-Alt were determined by UV–vis spectroscopy analysis. SEM and TEM analysis revealed the uniform morphology of AgNPs-Alt with an average size of ~50 nm. The crystalline nature of the AgNPs-Alt was confirmed by XRD analysis. The interactions of alternan functional groups with silver was observed by FTIR analysis and thermal characteristics of AgNPs-Alt were determined by DSC analysis. Finally, the antibacterial and the antifungal activities of AgNPs-Alt were tested and AgNPs-Alt revealed inhibitory effects to pathogenic strains at 0.25 mg ml−1 concentration and this activity was observed to be concentration dependent. For the antifungal activity, a higher level of AgNPs-Alt was required compared to the antibacterial activity.
AtıfScopus35WoS31OpenAlex36İncele - MakaleYalnız künye2020Scopus SJRQ1Natural radioactivity of barite concrete shields containing commonly used supplementary materials
Gökçe, H.S.; Canbaz Öztürk, B.; Çam, N.F.; Andiç-Çakır, Ö.
The recycling of hazardous materials within new composites has a sustainable importance as it contributes on the reduction of high radionuclide concentrations. In this study, the effect of cementitious materials i.e. viscosity modifier, silica fume and fly ash on the 226Ra, 232Th and 40K activity levels of barite concrete shields was researched by using different mixing compositions in terms of binder content, w/b ratio and the amount of supplementary cementitious materials. In comparison to cement, silica fume and fly ash used in the production of concrete shields were found to have significantly higher activity levels of 40K, as well as 226Ra, 232Th and 40K, respectively. The 226Ra, 232Th and 40K activity levels of concrete shields range between 2.2 and 20.7 Bq kg−1; 2.6 and 7.0 Bq kg−1; 51.5 and 89.3 Bq kg−1, respectively. These activity values were found similar or less than those of building materials in the world. These satisfactory results are mostly caused by the barite source which has lower radioactivity levels. The concrete mixture details used in the study caused significant variation in the natural radioactivity of barite concrete shields. The introduction of silica fume which has high 40K activity levels and fly ash with high 226Ra, 232Th and 40K activity levels compared to cement and barite aggregate, significantly increased the radiological hazard parameters, although all results were found to be below the limits recommended by international reports. In conclusion, 226Ra activity levels of the concrete shields were significantly increased (up to 8.4 times) by the variation of mix design parameters used in comparison with concrete mixtures that have the least 226Ra activity level. The 232Th and 40K activity levels were as well increased in relatively less amounts (1.7 and 0.73 times higher, respectively).
AtıfScopus22WoS20OpenAlex23İncele - MakaleAçık Erişim2021Scopus SJRQ2Relationship between hydraulic and geoelectrical parameters for alluvial aquifers in Bursa, Turkey—a case study
Eryılmaz Türkkan, Gökçen; Korkmaz, Serdar
This research aims at analyzing the relationship between the hydraulic conductivity and the formation factor in alluvial aquifers. The study was conducted on the alluvial aquifers within the province of Bursa, Turkey. Field surveys were carried out on 12 different locations each having alluvial formation. Initially, slug tests were applied at the wells and hydraulic conductivity values were calculated by using Bouwer-Rice and Dagan analytic methods. Afterwards, vertical electrical sounding method with Schlumberger array was applied on these locations to obtain apparent resistivity. These values were then converted to real resistivity under IPI2WIN software. Water samples were taken from the wells, and their electrical conductivity values were measured in the laboratory which were converted to water resistivity. Finally, formation factor was calculated as a ratio of real resistivity to water resistivity. The variations of hydraulic conductivity and transmissivity values against the formation factor were examined, and a linear relation was observed. Furthermore, their variations against modified formation factor and modified aquifer resistivity were also investigated and similarly linear relationships were observed. The graphs obtained conform to the results of similar studies in literature and will serve as a guideline for prospective groundwater research in the study area.
AtıfScopus3OpenAlex2İncele - MakaleYalnız künye2020Scopus SJRQ3Macronutrient and micronutrient levels and phenolic compound characteristics of monofloral honey samples
Bayram, Nesrin Ecem; Canli, Deniz; Gercek, Yusuf Can; Bayram, Sinan; Çelik, Saffet; Güzel, Fatma; Morgil, Hande; Oz, Gul Cevahir
This study aimed to obtain data on specific properties of various monofloral honey samples. Palynological, phenolic component, macroelemental and microelemental analyses were conducted and antimicrobial activities of honey samples were determined. In addition, protocatechuic acid for pine, lavender (from Isparta), heather (from Mugla) and cedar honey; gallic acid for carob, oak, lavender (from Antalya), chestnut, sandalwood and heather (from Antalya) honey; caffeic acid for linden, astragalus, chaste honey; syringic acid for rhododendron honey and the quercetin compound for cornelian cherry-citrus honey were observed to be dominant. As a result of the elemental analyses performed with inductively coupled plasma mass spectrometry, it was determined that elemental profiles of all of the honey samples differed, and the total ratio of macrominerals sodium, potassium, calcium, phosphorus and magnesium was the highest in the oak honey and the lowest in the cornelian cherry-citrus honey. According to antibacterial activity test results, Gram-negative bacteria were found to be more resistant to the honey samples compared to Gram-positive bacteria. In conclusion, the results of this study confirmed that the origin (blossom or honeydew) and plant source of the honey samples had an effect on their elemental content, phenolic component and antimicrobial activity.
AtıfScopus45İncele - MakaleAçık Erişim2022Scopus SJRQ3An investigation of mathematics teachers' specialized content knowledge related to basic concepts about sets
Yazici, Nurullah; Albayrak, Mustafa
This research was carried out in order to examine the specialized content knowledge of mathematics teachers related to teaching basic concepts about sets within the MKT Model. In this study, a holistic single-case study design is used in qualitative research methods. The study group consists of 18 mathematics teachers at different educational background and professional experience in teaching sets selected through the sampling of criterion, which is working in different high schools in one province in the Mediterranean region in the academic year 2016-2017. Research data were obtained using semi-structured interview, observation and document analysis techniques. In the analysis of obtained data, descriptive analysis, content analysis, continuous comparison techniques and special data analysis methods were used together with each data collection tool. The findings of the research show that teachers gave correct answers to the questions asked about the basic concepts of "Why?" in the sets. However, it is clear that the teachers cannot write sufficient reason why the asked questions are "Why?". As a result of the research, it has been determined that the teachers have superficial knowledge about the concepts of "Set, Universal Set, Infinite Set" and "Equal Set". However, it was determined that teachers made explanations with a general mathematical knowledge based on the characteristics of the concept rather than providing persuasive mathematical explanations to the questions asked.
AtıfOpenAlex1TR Dizin1İncele - MakaleAçık Erişim2021Scopus SJRQ2Experimental and Numerical Investigation of Levitation Force Parameters of Novel Multisurface Halbach HTS-PMG Arrangement for Superconducting Maglev System
Ozturk, Kemal; Badia-Majos, Antonio; Abdioglu, Murat; Dilek, Durukan Burak; Gedikli, Hasan
We have designed multisurface Halbach high temperature superconductor-permanent magnetic guideway (HTS-PMG) arrangements for magnetically levitated transportation (Maglev) and investigated the static force parameters in addition to the dynamic response characteristics. Three different Halbach HTS-PMG arrangements were used with multisurface (6 HTS, 4 HTS) and single surface (2 HTS) configurations and static and dynamic measurements were carried out in three different field cooling heights (FCHs). The bigger vertical loading capacity and wider loading gap were obtained with multisurface Halbach HTS-PMG arrangements. In addition, nearly four times bigger guidance force values of multisurface arrangements than that of single surface one indicates that the side HTSs in multisurface arrangements make a significant contribution to the guidance force and thus lateral movement stability of Maglev systems. Both the vertical and lateral dynamic stiffness values increased with decreasing FCH and it can be also said that the dynamic stiffness properties of Maglev systems can be enhanced especially in lateral direction by using the multisurface Halbach HTS-PMG arrangements. Understanding of these experimental observations is supported by dedicated theoretical modelling through a 2-D approximation of the system. We show that by using a single material parameter (the critical current density J_bf c) for the whole superconducting set, one may satisfactorily predict the complete series of experiments. The static and dynamic parameters obtained from this study and the results of dedicated theoretical modeling for single-surface and multisurface HTS-PMG arrangements are thought to be helpful for the researchers working on static and dynamic performances of HTS Maglev systems.
AtıfScopus28WoS22OpenAlex26İncele
