Bayburt ÜniversitesiBayburt ÜniversitesiAçık Erişim Arşivi · RDL Open

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  • MakaleAçık Erişim2020Scopus SJRQ3
    Effect of loading rate on cohesive parameters of the adhesive Araldite 2015

    Erbayrak, Engin; Ozer, Halil

    This study addresses the effect of loading rates on cohesive parameters and microstructural composition of the Araldite 2015 adhesive. Double Cantilever Beam (DCB) samples were tested under the loading rates of 1, 5, 10, 20, 100 and 200 mm x min(-1). The Park-Paulinho-Roeser model (PPR model) was used to get cohesive parameters. In modelling of the softening behavior, inverse analyses were performed using the date obtained from the PPR softening curves. It was seen that the fracture energy and cohesive parameters are decreasing with increasing the loading rate. However, there seems to be a transition region where the fracture energy nearly remains constant. Microstructural analyses were implemented in order to study the effects of the loading rates on the characteristics of the fracture surfaces. It was concluded that the loading rates greatly influence the distribution of micro-voids in the epoxy matrix. Moreover, the presence of voids in epoxy matrix improved the plastic deformation around the crack tip and increased the fracture toughness.

    AtıfWoS3
    Web of Scienceİncele
  • MakaleYalnız künye2020
    The Effect of Protein and Carbohydrate Consumption during 10-Week Strength Training on Maximal Strength and Body Composition

    Ozan, Murat; Buzdagli, Yusuf; Siktar, Erdinc; Ucan, Izzet

    In this study, it was aimed to examine the effect of protein and carbohydrate consumption on repetitive maximal strength and body composition during the 10-week strength training. The mean age and height of the groups are as follows; experimental group CAR: (n=10) 20.04 +/- 1.38 years, 173.44 +/- 4.62 cm, PR (n=10) 21.29 +/- 2.44 years, 177.24 +/- 4.22 cm and placebo group; PLA (n=10) 20.14 +/- 2.19 years, 174.15 +/- 5.12 cm in total and 30 inactive male individuals participated in the evaluation. The research was conducted as a single blind study. Scitec Isolate Whey Protein and Hardline Carbopure supplementation was given to the experimental groups under the researcher supervision for 10 weeks in appropriate for daily use type and dose. 0.75 g/kg protein was given to the PR group two hours before the training, 0.75 g/kg protein was given immediately after the training and totally 1.5 g/kg 500ml water and protein supplement was given on the days of training. In carbohydrate supplementation, carbohydrate supplements were applied as 3.0 g/kg two hours before the training and 3.0 g/kg immediately after the training, and a total of 6 g/kg 500m1 water on the days of training. In the research, synthetic colorant, which does not increase blood sugar, was given to the PLA group with 500m1 water in equal amounts to the given supplement. As a result; while the use of carbohydrate and protein supplements in the 10-week strength training performed 4 days a week provided positive improvements on body composition and 1MT, especially the use of protein provided more positive developments on fat percentage and lean body mass.

    AtıfWoS3
    Web of Scienceİncele
  • MakaleYalnız künye2020Scopus SJRQ4
    Some physicochemical and microbiological properties of butter produced in Erzurum

    Akgül, Halil Ibrahim; Sengül, Mustafa; Ürkek, Bayram; Kotan, Tuba Erkaya; Gürbüz, Zeynep

    The goal of this study was to determine some physicochemical and microbiological properties of Erzurum butter. Random samples (n = 30) were collected from different retail markets throughout Erzurum province. The pH, acidity, and melting point values of samples were 3.88, 0.47%, and 30.03 degrees C, respectively. The salt, fat, and moisture values of some samples (sample no 1, 14, and 18) were not harmony with Turkish Food Codex. The highest and lowest peroxide, iodine, saponification, Reichert-Meissl (RM), and Polenske values were found to be in the range of 0-0.51 mEqO2/kg, 22.97-38.64, 195.45-228.54, 17.08-30.-56, and 0.72-1.80, respectively. The refractive index value (RI) was changed from 1.4591 to 1.4620. Total coliforms, aerobic mesophilic bacteria (TAMB), lactic acid bacteria (cultured in MRS and M17), and mould and yeasts mean counts were 1.07 log CFU g-1, 6.79 log CFU g-1, 6.45 log CFU g-1, 6.76 log CFU g-1, and 5.33 log CFU g-1, respectively. There were high differences in physicochemical and microbiological properties of butter might be attributed to a non-standard production process as well as non-standard raw material. In sum, the sanitation and storage conditions should be improved from production to consumption to improve the butter quality.

    AtıfWoS1
    Web of Scienceİncele
  • MakaleYalnız künye2020Scopus SJRQ3
    Effect of resin content on tribological behavior of brake pad composite material

    Yanar, Harun; Ayar, Hasan Huseyin; Demirtas, Muhammet; Purcek, Gencaga

    Purpose This paper aims to investigate the effect of straight phenolic resin content on the fade behavior, frictions and wear characteristics of pre-determined brake pad composite matrix having specific amount of barite (BaSO4), rock wool, Kevlar, graphite and magnetite. Design/methodology/approach Different amount of resin ranging between 16 and 20 wt. per cent were added by changing only the filler (barite) content of composite matrix. Subsequently, friction and wear behavior of the composite samples were analyzed using a special pin-on-disc type test system developed for brake pad sample. The worn surfaces were investigated by SEM and three-dimensional (3D) surface profilometer. Findings The average coefficient of friction (CoF) of composite samples and temperature of the disc surface showed a linear increase with decreasing the resin content. The sample having 20 wt. per cent resin showed the minimum wear rate with smooth worn surface. But the amount of fade is quite high in that sample. Decreasing resin content decreased the fade formation, and the composite with 16 per cent resin brought about the minimum fade formation. As the fade formation is unwanted in brake pad applications, the composite with 16 wt. per cent resin was proposed as the most appropriate one considering the performance parameters related to friction and wear. Originality/value This paper optimizes the resin content of composite brake pad materials to achieve the best combination of its tribo-performance and mechanical properties and provides valuable information for scientists and engineers working in that area.

    AtıfWoS8OpenAlex15
    Web of Scienceİncele
  • MakaleYalnız künye2020
    The Effects of Strenght Exercises on Body Composition and Irisin

    Ozan, Murat; Karakurt, Sercan; Aggon, Eser; Agirbas, Ozturk; Ucan, Ezzet; Alp, Hamit Hakan

    This is the first study to determine the effects of strenght exercises on irisin and correlation of bady composition and irisin. The purpose of this study was to determine the effects on body composition and irisin of static strength exercises with Tera-Bant (R) in elite boxers. 9 volunteered elite male boxers participate in the study who are nonsmokers and did not use any nutritional supplements. Boxers were instructed to perform strength exercises with Thera-Band for 3 days a week for 8 weeks. Blood samples were taken before exercises (resting), after the first exercise (acute) and after 8 weeks following the last exercise (chronic), and measurement of body fats were made at the same time. Irisin levels of blood were examined. Statistical analyses were carried out using the SPSS 22 for Windows. The data were found to not be distributed normally. Thus, Friedman, Wilcoxon, Mann-Whitney U and Speraman's correlations tests were used. The results were evaluated using an alpha level of .05. Body Fat Percentage (BFP) and Fat Mass (FM) levels of athletes increased, Lean Mass (LM) decreased relatively both after a single session and after 8 weeks. While irisin concentration increased after a single session, (correlation in pre exercise and after a single exercise. Static strength exercise is effective on body fat both acutely and chronically, and effective on irisin only acute. Farther, the body fat and irisin are related to the negative.

    AtıfWoS2
    Web of Scienceİncele
  • MakaleAçık Erişim2020Scopus SJRQ1
    Development of Eco-Efficient Fly Ash-Based Alkali-Activated and Geopolymer Composites with Reduced Alkaline Activator Dosage

    Gökçe, H. S.; Tuyan, M.; Ramyar, K.; Nehdi, M. L.

    The eco-efficiency and economy of geopolymer composites largely depend on their alkaline activator dosage. In this study, the effect of applying a pre-setting pressure and variation of the aggregate-to-fly ash ratio on the alkaline solution dosage and mechanical strength of fly ash-based geopolymer composites was explored. It is shown that through control of the aggregate-to-ash ratio and application of pre-setting pressure, compressive strength could be increased by 102% and 86% for Class F fly ash-based geopolymer and alkali-activated Class C fly ash-based mixture, respectively. The total alkaline solution consumption could be reduced from 718 to 188 kg/m(3) and from 769 to 262 kg/m3 for Class F fly ash-based geopolymer and alkali-activated Class C fly ash-based mixture, respectively. The proposed method reduced the alkaline solution consumption per compressive strength (6.2 kg.m(-3).MPa-1) by up to 85% compared to that of the reference manually consolidated control geopolymer. The findings demonstrate that fly ash-based geopolymers could be made more sustainable and eco-efficient through tailored production techniques. (C) 2019 American Society of Civil Engineers.

    • SDG 12 · Sorumlu Üretim ve Tüketim
    AtıfWoS23OpenAlex30
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  • MakaleAçık Erişim2020Scopus SJRQ2
    Comparison of two wild-grown Berberis varieties based on biochemical characterization

    Çakır, Özlem; Karabulut, Abdulkadir

    In this study, some physicochemical properties, antioxidant activity, total phenolic content, mineral content, and phenolic profiles of Berberis vulgaris and Berberis crataegina wild-grown in Bayburt are analyzed and compared. The level of total phenolic content in B. crataegina DC. (73.48 µg GAE/mg KM) was found higher than B. vulgaris (71.54 µg GAE/mg KM). According to three methods (β-carotene, 2,2-diphenyl-1-picrylhydrazyl, and cupric reducing antioxidant capacity) the antioxidant activity of the B. crataegina is also higher. The change in color (L*, b*) is found statistically important (p <.05). There are no meaningful differences between the dry matter, C vitamin, pH value, and water activity (p >.05). It was observed that the fruit type has a great effect on brix and ash content (p <.05) and glucose, total sugar, and malic acid content. Chlorogenic acid is the dominant phenolic component for both types. It is followed by syringic, sinapic, and gallic acid in B. vulgaris and sinapic, syringic, and gallic acid in B. crataegina. Practical applications: Wild fruits have been consumed for centuries in nutrition or pharmacology applications. They are known as rich resources of antioxidant and phenolic compounds. For that reason, wild fruits play an important role in the prevention and treatment of some diseases especially cardiovascular diseases and cancer. In this study, wild-grown B. vulgaris and B. crataegina were analyzed in detail according to their bioactive properties and an assessment was made in terms of industrial and medical usability. This study reports mineral content, antioxidant activity, total phenolic content, and the phenolic acid profile (sinapic, syringic, gallic, chlorogenic, caffeic, vanillic, trans-ferulic, p-coumaric, and 4-hydroxybenzoic acids) of two Berberis varieties. According to results, these fruits may be used as natural flavoring and coloring material in food sector. Thanks to the active ingredients and minerals; these fruits may be used in pharmaceutical industry. They have a good potential for commercial exploitation and positive effects on health.

    • SDG 2 · Açlığa Son
    AtıfScopus16WoS8OpenAlex16
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  • MakaleYalnız künye2020Scopus SJRQ1
    Structural and physicochemical characterisation and antioxidant activity of an α-D-glucan produced by sourdough isolate Weissella cibaria MED17

    Aburas, Hani; İspirli, Hümeyra; Taylan, Osman; Yilmaz, Mustafa Tahsin; Dertli, Enes

    An exopolysaccharide (EPS) producer slimy-mucoid type colony was isolated from sourdough and identified as Weissella cibaria MED17. The 1H and 13C NMR spectra of EPS MED17 demonstrated that this EPS was a dextran type glucan ((1 → 6)-linked α-D-glucose core structure) containing (1 → 3)-linked α-D-glucose branches and proportion of (1 → 6)-linked α-D-glucose units to (1 → 3)-linked α-D-glucose units was 94.3:5.7%. The FTIR analysis also confirmed the (1 → 6)-linked α-D-glucose linkage. A high level of thermal stability was observed for glucan MED17 as no degradation up to 300 °C was observed by TGA and DSC analysis. The XRD analysis of glucan MED17 showed its semi- crystalline nature and its compact sheet-like morphology was observed by SEM analysis. Finally, antioxidant characteristics of glucan MED17 were determined by ABTS and DPPH radical scavenging activity tests that revealed a moderate antioxidant activity of glucan MED17. These findings show potential techno-functional characteristics of glucan MED17.

    AtıfScopus58WoS55OpenAlex59
    ScopusWeb of SciencePubMedİncele
  • MakaleYalnız künye2020Scopus SJRQ3
    The quality characteristics and shelf life of probiotic ice cream produced with saruc and Saccharomyces boulardii

    Salik, M.A.; Arslaner, A.

    Ten types of classic and probiotic (Saccharomyces boulardii) ice cream were produced using different mixture combinations containing 10 or 20% Saruc, a traditional Turkish snack containing dried Cimin grape, Kemah walnut, and 0.5 or 1.0% grape seed. Physical, chemical, and microbiological analyses conducted during the storage period (days 1, 15, 30 and 60 at-20 ± 1°C) were used to assess the probiotic shelf life and quality properties of the ice cream samples. The desired therapeutic effects of S. boulardii levels in probiotic products were from 106 to 108 CFU/g during storage. The results revealed that Saruc, grape seed, and S. boulardii had a significant effect on the quality properties of ice cream samples. Titration acidity, total dry matter, fat, protein, ash, glucose, fructose, total sugar, viscosity, first dripping time, complete melting time, a& value, and calorie (kcal) values increased with increasing concentration of Saruc. However, pH, sucrose, melting rate, L&, and b& values decreased. Grape seed increased titration acidity, protein, fat, ash, viscosity, first dripping time, complete melting time, and calorie values in all samples, but decreased the pH values. The addition of Saruc and grape seed positively affected the growth and viability of S. boulardii at levels from 106 to 108 CFU/g during storage. Taking all the quality parameters into consideration, it was shown that with the addition of Saruc, grape seed, and S. boulardii, new functional ice creams with high nutritional value could be produced.

    AtıfScopus14
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  • MakaleYalnız künye2020Scopus SJRQ2
    Honeys from some different regions of Azerbaijan: bioactive characteristics based on phenolic profile and antioxidant activity

    Degirmenci, Atiye; Can, Zehra; Boyraci, Gulsum Merve; Yildiz, Oktay; Asadov, Elsevar; Kolayli, Sevgi

    Azerbaijan is an important region for the beekeeping and honey industry. Biochemical characteristics of eleven honey samples from different regions of Azerbaijan were analyzed through measuring electrical conductivity, optical activity, moisture content, proline and diastase number. Phenolic components are analyzed by reverse-phase high-performance liquid chromatography (RP-HPLC) with UV–Vis double beam detector. Sugars profiles of samples were carried out using HPLC with a refractive index detector (RID). Total phenolic content (TPC), ferric reducing antioxidant power (FRAP) and 2,2-diphenyl-1-picryhydrazyl (DPPH) free radical scavenging activity were measured with the aim of gathering information on the antioxidant power of samples. Biochemical and antioxidant characteristics are also supported with melissopalynological data. Conductivity ranged between 0.32 and 0.82 mS cm−1, moisture 14.52 and 20.78%, proline 314.34 and 1077.21 mg kg−1, diastase 13.05 and 22.19. Azerbaijan honeys exhibited levorotatory properties. Total phenolic content varied from 18.82 to 154.75 mg gallic acid equivalent per 100 g honey. The results confirm that physico-chemical and biologically active properties of Azerbaijan honeys are affected by the flora and geographical variations.

    • SDG 2 · Açlığa Son
    AtıfScopus17WoS16OpenAlex20
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  • MakaleYalnız künye2020Scopus SJRQ4
    Innovative flow risk assessment with climate change perspective in Yesilirmak Basin

    Serancam, Ugur; Dabanli, Ismail

    Surface temperature increase due to global warming results in polar ice melting, snow cover thinning, changes in precipitation anomaly. All these phenological effects alert engineers, planners and administrators to be more sensitive against climate change-based risk effects on water structures. Vulnerability to natural disasters such as floods and droughts are expected to occur more frequent than past. Therefore, design and potential evaluation of water structures such as transmission channels, water wells, dams and hydraulic power generation facilities need to be re-evaluation. This re-evaluations procedure must be updated by taking into consideration climate change impacts with their risk assessments. For this purpose, the climate change-based risk levels are calculated from historically available records through possible trend tendencies, which are expressed in terms of trend slope. It has been observed that, in general, the climate change impacts are not significant on precipitation and runoff. This is due to the low trend slopes in the standardized hydro-meteorological time series. This point has been documented for Yesilirmak basin, where the climate change impact is very limited.

    AtıfScopus1
    Scopusİncele
  • MakaleYalnız künye2020Scopus SJRQ1
    Terrorism - workers’ remittances nexus: empirical evidence from Turkey

    Arİ, Yılmaz Onur; Bello, Ibrahim

    The paper examines the impacts of remittances on terrorism for Turkish economy by using annual time series data covering the period of 1990-2019. Autoregressive Distributed Lag (ARDL) was used in the application of econometric method. To ensure robustness of results, the study accounts for structural breaks in the unit root test and the co-integration analysis. The results obtained indicated that remittances flows to Turkey have a positive and significant effect on terrorism. This is in line with the empirical evidence that finances through remittances can promote terrorism in a country. The study also concludes that unemployment has strong a correlation in promoting terrorism in Turkish economy and that persistent unemployment can cause economic inequality, poverty, social dislocation, unrest, and conflict such as terrorism, which has a negative impact on subsequent long-run economic growth. Besides, trade openness shows a negative but significant effect, which indicates that trade openness has a little influence in promoting terrorism.

    AtıfScopus2
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  • MakaleYalnız künye2020Scopus SJRQ3
    Some harmonic problems on the tangent bundle with a berger-type deformed sasaki metric

    Altunbas, Murat; Simsek, Ramazan; Gezer, Aydin

    Let (M2k, ϕ, g) be an almost anti-paraHermitian manifold and (T M, gBS) be its tangent bundle with a Berger type deformed Sasaki metric gBS . In this paper, we deal with the harmonicity of the canonical projection π: T M → M and a vector field ξ which is considered as a map ξ: M → T M.

    AtıfScopus9
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  • MakaleAçık Erişim2020Scopus SJRQ3
    Effect of probiotics supplementation on adipokine profile (Visfatin, adiponectin and chemerin), intestinal (citrulline) and thyroid function in japanese quail subjected to heat stress; [Einfluss einer probiotischen futterergänzung auf das adipokin-profil (Visfatin, adiponectin und chemerin), und die darm- (citrullin) und schilddrüsenfunktion japanischer wachteln unter hitzestress]

    Bayraktar, B.; Tekce, E.

    In this study, we aimed to determine the effect of probiotic supplementation of Lactobacillus reuteri E81 (LRE; 200, 400, 600 mg/kg) to the diets of Japanese quail (Coturnix coturnix japonica) reared under heat stress (HS) on serum adipokine (visfatin, adiponectin and chemerin), intestinal (citrulline) and thyroid hormone levels. On day 7 of the trial, the animals were assigned to 8 groups [Control temperature (CT): control (C, without LRE supplementation), LRE-200, LRE-400 and LRE-600 and HS: control (HSC), SLRE-200, SLRE-400 and SLRE-600], each composed of 56 animals of equal body weight. Each group was divided into 4 subgroups withg 14 animals per compartment. During the experiments, the temperature applied to the CT-groups C, LRE-200, LRE-400 and LRE-600 was 25°C and to the HS-groups HSC, SLRE-200, SLRE-400 and SLRE-600 was 37°C. At the end of the study (days 21 and 42), a dose-dependent decrease in citrulline, chemerin, adiponectin, and thyroid hormones and a dose-dependent increase in the visfatin hormone level (p < 0.01) due to LRE supplementation were observed in the HS and CT groups compared to its control. In conclusion, the present study showed that dietary supplementation with 600 mg/kg of LRE affected serum chemerin, adiponectin, T3, T4, TSH and visfatin levels in Japanese quail raised under heat stress (p < 0.001).

    • SDG 2 · Açlığa Son
    • SDG 3 · Sağlık ve Kaliteli Yaşam
    AtıfScopus6WoS5OpenAlex2
    ScopusWeb of Scienceİncele
  • MakaleYayıncıda açık erişim2020Scopus SJRQ2
    Effects of an Essential Oil Mixture Added to Drinking Water for Temperature-Stressed Broilers: Performance, Meat Quality, and Thiobarbituric Acid-Reactive Substances

    Tekce, E.; Çınar, K.; Bayraktar, B.; Takma, Ç.; Gül, M.

    This study investigated the effects of an essential oil mixture (EOM; Eucalyptus globulus labill, Tymus vulgaris, Cymbopogon nardus, and Syzgium aromaticum) added to drinking water on temperature-stressed broilers. The performance parameters (body weight, average daily weight, feed intake, and feed conversion ratio), meat quality, and thiobarbituric acid-reactive substances (TBARS) were evaluated. In a 42-d study, 400 Ross-308 male chickens (1-d-old) were randomly assigned to 8 different groups (n = 50), each containing 4 subgroups (n = 8) (22°C Control (C), C + 250 mL/1,000 L, C + 500 mL/1,000 L, C + 750 mL/1,000 L), 36°C (stress control (SC), SC + 250 mL/1,000 L, SC + 500 mL/1,000 L, SC + 750 mL/1,000 L). Adding 750 mL/1,000 L at 22°C and 250 mL/1,000 L at 36°C was more beneficial to the fattening performance parameters than those in the control group. EOM reduced liver weight but increased abdominal fat in the SEOM-250 groups but did not affect other organ weights. EOM had no effect on the TBARS or the b* color parameter while it augmented the a* and L* coordinates of meat color.

    • SDG 2 · Açlığa Son
    AtıfScopus29WoS25OpenAlex23
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  • MakaleAçık Erişim2020Scopus SJRQ2
    Switching linear quadratic Gaussian control of a flexible blade structure containing magnetorheological fluid

    Sivrioglu, Selim; Bolat, Fevzi Cakmak

    The present study suggests a new active control structure with a switching algorithm for control current of the electromagnetic actuator to suppress vibrations of a flexible blade element containing magnetorheological (MR) fluid. An identification model between MR fluid inside the blade and the electromagnetic actuator is utilized to derive the force equation. Since only one electromagnet is employed to suppress the blade vibration, a single-sided control actuation occurs in the proposed system. Therefore, the pulling force used for vibration control is generated by the actuator when the blade moves to downward direction. A switching linear quadratic Gaussian (LQG) controller that produces always a positive control input is designed to attenuate the blade vibrations. The LQG controller with switching is experimentally implemented under the impact and steady-state aerodynamic disturbances. The results of experiments show that the proposed switching controller is effective to attenuate vibrations of the flexible blade element.

    AtıfScopus15WoS11OpenAlex13
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  • MakaleYalnız künye2020Scopus SJRQ1
    Probiotic properties of lactic acid bacteria strains isolated from pastırma

    Topçu, Kübra Cinar; Kaya, Mükerrem; Kaban, Güzin

    In this study, the probiotic properties of 80 lactic acid bacteria (LAB) strains isolated from pastırma, a dry-cured meat product, were investigated. For this purpose, strains were investigated for their resistance to bile salt and hydrophobicity abilities. In 6 strains selected as a result of these analyses, development at high salt concentrations, auto-aggregation and co-aggregation, resistance to low pH, and adhesion analyses were performed. The growth percentage of all strains decreased with increasing bile salt concentration at both 25 °C and 37 °C. P. pentosaceus K7, K41, K44, K51 and K81 and P. acidilactici K99 gave the highest values in terms of hydrophobicity ability. The highest auto-aggregation and the highest co-aggregation were found in P. pentosaceus K41 (17.62%) and P. pentosaceus K44 strain (26.23%), respectively. These six strains showed tolerance to high acidity even at pH 2. The strains significantly maintained their viability in the simulated gastric and intestinal fluids. Furthermore, the strains had low adhesion capacity in Caco-2 and HT-29 cell lines and generally showed resistance under gastrointestinal system conditions. As a result, P. pentosaceus K44, P. acidilactici K99 and P. pentosaceus K41 could be considered as probiotic strains.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
    AtıfScopus55WoS48OpenAlex50
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  • MakaleYayıncıda açık erişim2020Scopus SJRQ3
    Determination of physicochemical and microbiological properties and fatty acid composition of butter produced in Trabzon, Turkey

    Akgül, Halil İbrahim; Şengül, Mustafa; Ürkek, Bayram; Kotan, Tuba Erkaya

    In this study, the some physicochemical properties, fatty acid compositions and microbiological properties of butter samples were studied. Butter samples (n = 30) were randomly collected from different local markets. Thus, butter samples were evaluated in terms of Turkish regulations, food safety and quality. The mean values of the butter samples for peroxide value (PV), iodine value (IV), saponification value (SV), Polenske value, Reichert-Meissl (RM) and Refractive index (RI) values were determined as 0.85 mEqO2 kg-1, 30.03, 220.09, 1.30, 25.60 and 1.4611, respectively. The moisture and fat values were not in harmony with Turkish Food Codex Butter, Other Milk Fat Based Spreadable Products and Anhydrous Milkfat Notification (the highest moisture content 16%, the lowest fat content 80%) in 23 and 13 butter samples, respectively. The salt values were coherent with Turkish Food Codex in all butter samples. Conjugated linoleic acid (CLA) rate of the butter samples was ranged from 0.15 to 1.32%. The average values of coliforms, total aerobic mesophilic bacteria (TAMB) and mould and yeasts counts were determined as 1.67, 6.33 and 5.22 log CFU g-1, respectively.

    AtıfScopus13WoS10
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  • MakaleYayıncıda açık erişim2020Scopus SJRQ1
    Temperature dependent current- and capacitance-voltage characteristics of W/n-Si structures with two-dimensional WS2 and three-dimensional WO3 interfaces deposited by RF sputtering technique

    Baltakesmez, A.; Tekmen, S.; Güzeldir, B.

    In this study, tungsten disulfide (WS2) and tungsten trioxide (WO3) thin films are deposited on n-Si by RF sputtering technique. The optical, morphological and structural characteristics of these films are investigated. The XRD patterns showed that highly crystallinity have been obtained with dominant characteristic diffraction peaks of the WS2 and WO3. The SEM images show that these films are nearly uniform and covered all surface of substrates. Furthermore, the WS2 film has two-dimensional (2D) vertical layers while the WO3 has three-dimensional (3D) structure. From the XPS spectra, it revealed that the peaks confirmed the formation of WS2 and WO3 phases. The Raman spectra presented that different vibrational modes and phases are characteristics of the WS2 and WO3 thin films. Electrical properties of W/n-Si metal-semiconductor (MS) and W/WS2/n-Si and W/WO3/n-Si metal-interfacial layer-semiconductor (MIS) diodes are investigated using current-voltage (I-V) and capacitance-voltage (C-V) characteristics at various temperatures. It was found that I-V and C-V characteristics are strongly dependent on temperature and the interfacial WS2 and WO3 layers are significant roles for the electrical properties of W/WS2/n-Si and W/WO3/n-Si devices.

    AtıfScopus19WoS20OpenAlex17
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  • MakaleAçık Erişim2020Scopus SJRQ2
    Investigations of Strain Rate Effects on the Mechanical Properties of Hybrid Composite Laminate Under Varying Temperatures

    Erbayrak, Engin; Gumus, Beril Eker; Yuncuoglu, Ercument Ugur; Kahraman, Yusuf

    The mechanical behavior of hybrid composite laminates under varying strain rates and temperatures was investigated in this study. The hybrid composite laminate is constituted as a sequential stacking sequence of plain-woven carbon-fiber-reinforced epoxy (CFRE) and plain-woven glass-fiber-reinforced epoxy (GFRE) laminates. Vacuum-assisted resin transfer molding (VARTM) process was used to fabricate the composite laminates. Hybrid composite laminates (HCGFRE) were tested under four different strain rates (0.05 min−1, 0.5 min−1, 2.5 min−1, 5 min−1) and three different temperatures (RT, 60 °C, 100 °C). Microstructure analysis was performed to observe the voids, fiber delamination and matrix failure occurring in the composite laminate. In numerical analyses, continuum damage mechanics material model (MAT 58) was utilized in LS-DYNA® explicit finite element program to simulate the mechanical properties of CFRE, GFRE and HCGFRE laminates. It was determined that the tensile strength of all composite laminates is increasing by increasing the strain rates in all temperatures. The continuous damage mechanics material model (MAT 58) was found to be suitable for simulating woven composite laminate under different strain rates and temperatures. In microstructural study, it was not observed significant changes in the microstructure of composite laminates by changing strain rates.

    AtıfScopus1WoS1OpenAlex3
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