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Öğe Antioxidant capacity and fatty acid composition of different parts of Adenocarpus complicatus (Fabaceae) from Turkey(Revista De Biologia Tropical, 2014) Berber, Adnan; Zengin, Gokhan; Aktumsek, Abdurrahman; Sanda, Murad Aydin; Uysal, TunaAdenocarpus complicatus is distributed throughout the Anatolian peninsula and is widely used for human and animal nutrition. The purpose of this work was to study the antioxidant properties and fatty acid composition of different parts of this plant (fruits and mixed materials). The species was collected from Golyuzu village of the Seydisehir district near Konya province, Turkey. Fruit and mixed parts obtained from this species were ground and a 15g sample was used to prepare methanolic extracts. Powdered plant samples were extracted with 100mL methanol in a mechanical shaker. The obtained extracts were filtered and concentrated to dryness under reduced pressure and were subsequently stored at -20 degrees C. Antioxidant components, namely total phenolic and flavonoid content, were detected for each extract using spectrophotometric methods. Antioxidant capacity was evaluated by various assays including phosphomolybdenum, DPPH free radical scavenging capacity, metal chelating activity, and ferric and cupric ion reducing power. The fatty acid profiles of plant parts were also determined by using gas chromatography. The total phenolic content of fruit (36.21mgGAE/g) was higher than that of mixed materials (13.79mgGAE/g). The methanolic extract of mixed material had higher amounts of flavonoid than fruit extract. The free radical scavenging activity of extracts was expressed as IC50 value (mu g/mL) (amount required to inhibit DPPH radical formation by 50%). The lower IC50 value reflects better free radical scavenging action. The radical scavenging activity of the samples was compared with BHT, it showed the mixed material to be almost two times more potent than the fruit extract. However, BHT is an excellent free radical scavenger with an IC50 of 34.061 mu g/mL. The ferric and cupric reducing power potentials of the extracts were expressed as EC50 value (the effective concentration at which the absorbance was 0.5). Fruit extract exhibited strong ferric reducing power with an EC50 of 871.25 mu g/mL. The metal chelating activity of the extracts increased with concentration. Chelating effect was 83.60% for fruit extract at 1mg/mL concentration. Oil content of fruit and mixed parts were detected as 6.71 and 6.14%, respectively. A total of 32 fatty acids were found in the oil. Essential fatty acids (linoleic and alpha-linolenic acid) were identified as the most abundant fatty acids in the oil. These results demonstrated that this plant species can be considered as an alternative to synthetic antioxidants. Likewise, the oil obtained from the plant can be used as a source of essential fatty acids for food and pharmacological applications.Öğe Antioxidant capacity and fatty acid composition of different parts of Adenocarpus complicatus (Fabaceae) from Turkey(Revista De Biologia Tropical, 2014) Berber, Adnan; Zengin, Gokhan; Aktumsek, Abdurrahman; Sanda, Murad Aydin; Uysal, TunaAdenocarpus complicatus is distributed throughout the Anatolian peninsula and is widely used for human and animal nutrition. The purpose of this work was to study the antioxidant properties and fatty acid composition of different parts of this plant (fruits and mixed materials). The species was collected from Golyuzu village of the Seydisehir district near Konya province, Turkey. Fruit and mixed parts obtained from this species were ground and a 15g sample was used to prepare methanolic extracts. Powdered plant samples were extracted with 100mL methanol in a mechanical shaker. The obtained extracts were filtered and concentrated to dryness under reduced pressure and were subsequently stored at -20 degrees C. Antioxidant components, namely total phenolic and flavonoid content, were detected for each extract using spectrophotometric methods. Antioxidant capacity was evaluated by various assays including phosphomolybdenum, DPPH free radical scavenging capacity, metal chelating activity, and ferric and cupric ion reducing power. The fatty acid profiles of plant parts were also determined by using gas chromatography. The total phenolic content of fruit (36.21mgGAE/g) was higher than that of mixed materials (13.79mgGAE/g). The methanolic extract of mixed material had higher amounts of flavonoid than fruit extract. The free radical scavenging activity of extracts was expressed as IC50 value (mu g/mL) (amount required to inhibit DPPH radical formation by 50%). The lower IC50 value reflects better free radical scavenging action. The radical scavenging activity of the samples was compared with BHT, it showed the mixed material to be almost two times more potent than the fruit extract. However, BHT is an excellent free radical scavenger with an IC50 of 34.061 mu g/mL. The ferric and cupric reducing power potentials of the extracts were expressed as EC50 value (the effective concentration at which the absorbance was 0.5). Fruit extract exhibited strong ferric reducing power with an EC50 of 871.25 mu g/mL. The metal chelating activity of the extracts increased with concentration. Chelating effect was 83.60% for fruit extract at 1mg/mL concentration. Oil content of fruit and mixed parts were detected as 6.71 and 6.14%, respectively. A total of 32 fatty acids were found in the oil. Essential fatty acids (linoleic and alpha-linolenic acid) were identified as the most abundant fatty acids in the oil. These results demonstrated that this plant species can be considered as an alternative to synthetic antioxidants. Likewise, the oil obtained from the plant can be used as a source of essential fatty acids for food and pharmacological applications.Öğe The effect of Diesel-Methanol Blends with Volumetric Proportions on the Performance and Emissions of a Diesel Engine(Kaunas Univ Technol, 2019) Berber, AdnanIn this work, the methanol is added to the diesel fuel in the volumetric proportions of 5%-%10-%15 to diminish negative environmental impacts of diesel engines. The diesel-methanol blends in the various proportions are tested in a single-cylinder direct-injection diesel engine. According to the test results, the addition of methanol to the diesel fuel causes a maximum decrease of 13.07 % in the engine torque, and a maximum decrease of 12.54 % in the specific fuel consumption. On the other hand, the exhaust emission results show that the values of CO and CO2 decrease 38.4 % and 5.04%. However, the increase of 3.66% in the exhaust gas temperature causes the increase of 17.1% in the NOx emission. Also, a significant decrease of 39.37% in the smoke opacity is observed compared to that of the diesel fuel. Although the addition of methanol to diesel fuel causes a slightly decrease in the engine performance, the diesel-methanol blends have a reasonable and considerable positive effect on environmental concerns of diesel engines.Öğe Effects of sinusoidal turbulator in cylindrical channel on heat transfer and flow characteristics(Maejo Univ, 2020) Altun, Aziz Hakan; Gurdal, Mehmet; Berber, AdnanEffects of heat transfer and flow characteristics on Reynolds numbers of different sinusoidal turbulators placed separately from a pipe in the turbulent flow were investigated experimentally. The experiments were carried out under forced flow and constant heat flow conditions. The elements, which drew a sine curve used as a turbulator, were positioned axially to the channel centre. The experiments were repeated for 3 width values of sinusoidal turbulators that correspond to 3D/4, D/2 and D/4 (D = inner diameter of test pipe). The experiments showed that although there were increases in the rate of heat transfer with the turbulator, they caused considerable pressure drop. As a result, as the width of the turbulator increased, the heat transfer ratio (the Nusselt number) and coefficient of friction increased. Increase in Nusselt number was about 39-86% at D/4 width, 70-119% at D/2 width and 72-170% at 3D/4 width. It was observed that the coefficient of friction was significantly affected by the width of the sinusoidal turbulator, being about 0.02 in the case of straight pipe, 0.184 - 0.242 at D/4 width, 0.345 - 0.415 at D/2 width, and 0.416 - 0.451 at 3D/4 width. In addition, increasing coefficient of friction increased pressure drop and power required for pumping.Öğe The electrical properties of ZnO/Si heterojunction diode depending on thin film thickness(Korean Physical Soc, 2022) Akin, Ummuhan; Houimi, Amina; Gezgin, Bahri; Gundogdu, Yasemin; Kilic, Sumeyye; Mercimek, Bedrettin; Berber, AdnanIn this work, ZnO thin films have been produced on p-Si wafer depending on number of laser pulses applied using pulse laser deposition (PLD) technique at room temperature conditions. Three different thicknesses of ZnO thin films (ZnO1, ZnO2 and ZnO3) have been produced by applying 18,000, 36,000 and 54,000 laser pulses and thicknesses of these produced three thin films have been measured to be 41 nm, 70 nm, 197 nm, respectively. It is observed in this work that while thicknesses of ZnO thin films increases, crystal structure of thin films develops, their grain size increase while their band gaps decrease. Ag/ZnO/Si/Au heterojunction diodes have been produced based on ZnO1, ZnO2 and ZnO3 thin films. After that, effect of thickness of thin film on electrical properties of diodes produced depending on number of laser pulses has been analyzed in detail. I-V characteristics of ZnO/Si heterojunction diodes produced have also been measured in darkness environment and under illumination conditions (AM 1.5 solar radiation of 80 mW/cm(2)) and results obtained have been interpreted and a conclusion has been made in this work. Furthermore, ideality factors, barrier heights and serial resistivities of these diodes have been calculated using conventional thermionic emission theory, Norde and Cheung-Cheung methods and then results obtained from analytical methods have been interpreted in detail in the present article. ZnO heterojunction diodes have exhibited photovoltaic properties under illumination conditions. It has been observed that as thickness of ZnO thin film is increased, J(sc) and eta values of the hetero junction diodes are increased. ZnO-3A hetero junction diode has exhibited the most improved photovoltaic performance. We have also theoretically investigated photo-electric properties of ZnO-3A heterojunction diode using SCAPS-1D packed software. The resulted J-V characteristics have been found very similar to measured counterparts.Öğe Experimental study on the heat transfer enhancement in a rectangular channel with curved winglets(Taylor & Francis Inc, 2022) Berber, Adnan; Gurdal, Mehmet; Yetimoglu, MuhammedEffects of the curved winglet vortex generator inserts (CWVGs) on the forced convection heat transfer, friction factor, and performance evaluation criteria (PEC) interior flow were experimentally examined in this work. The CWVGs manufactured in CNC from aluminum 6061 material were used as the expanded finned surface with different attack angles (alpha) of 0 degrees, 30 degrees, and 60 degrees. In the study, air was used as the fluid. The experiments were realized in the Reynolds number ranging from 6000 to 20000. The results showed that the CWVG insert in a rectangular channel ensured significantly higher Nusselt number than that of the channel without the insert through friction factor that was also increased. The Nusselt number and friction factor increased with the increase in the attack angle (alpha) of CWVG insert. The heat transfer enhancement by the CWVGs with attack angle of 0 degrees, 30 degrees, and 60 degrees ensured higher than that of the plain tube in the range of 217.39-291.30%, 260.86-465.21%, and 278.26-476.08%, respectively. The friction factors in the inner rectangular channel produced by the CWVGs with attack angle of 0 degrees, 30 degrees and 60 degrees, were about 8.93-10.33, 10.66-14.16, and 14.96-19.13 times above the plain tube, respectively. The performance evaluation criteria (PEC) for CWVGs with attack angle of 0 degrees, 30 degrees, and 60 degrees were in the range of 1.22-1.78, 1.28-1.86, and 1.32-1.89, respectively.Öğe Investigation of Performance of Heating and Cooling of Counter Flow Ranque-Hilsch Tubes with L/D=15, 16, 17, 18 for Brass(Trans Tech Publications Ltd, 2013) Dincer, Kevser; Berber, Adnan; Ozen, Dilek NurIn this study, heating and cooling performances of counter flow Ranque-Hilsch vortex tubes (RHVTs) were experimentally investigated for brass. The vortex tubes were made of brass. Diameter of vortex tube (D) was 10 mm. Length of vortex tube (L) was 15D, 16D, 17D and18D. The number of nozzles (Nn) was 5. The conical edges of the plugs have a slope of 30 degrees angle. Working pressure of Ranque-Hilsch was 460 kPa (absolute). According to the experimental results, the maximum heating performance of the RHVT system was found to be 39,5 degrees C at P-17 and the maximum cooling performance of the RHVT in this study was found to be -28,6 degrees C at P-18. An increase in fraction of cold flow (xi) led to a increase in the heating performance.Öğe Mathematical Model for Fuel Flow Performance of Diesel Engine(2016) Berber, AdnanIn this paper, response surface method (RSM) was proposed to determine fuel flow performance of an internal combustion diesel engine by using different specific conditions (injection pressure, engine speed and throttle position). Injection pressure of the diesel engine was chosen as 150 bars for turbocharger and pre-combustion chamber. Experiments were realized at four pressures corresponding to 100, 150, 200 and 250 bars each with throttle positions of 50, 75 and 100%. A mathematical model was used to predict fuel flow performance of engine according to pressures and throttle positions. The optimum performance conditions, for a required fuel flow, were obtained by using response surface method with 3D graphics. The developed prediction equations showed that the linear effect of engine speeds was the most important factor that influenced the fuel flow. Moreover, whether the proposed mathematical model of fuel flow is within the limits of the performance parameters has been considered.Öğe Prediction of heat transfer in a circular tube with aluminum and Cr-Ni alloy pins using artificial neural network(Taylor & Francis Inc, 2021) Berber, Adnan; Gurdal, Mehmet; Bagirsakci, KazimThis work aims to estimate the experimental heat transfer coefficients of a circular channel using artificial neural network. The experiments are carried out at a forced turbulent flow regime of 10,000 < Re <50,000. The obtained experimental Nusselt numbers are compared using the ANN (Artificial Neural Network). In the developed ANN structure are showed mean square error (MSE), average relative deviation (ARD %), and correlation coefficient (R-2) in modeling of overall experimental datasets of Nusselt number. As a result, it is observed that the heat transfer correlation predicted by ANN are sufficiently consistent with the experimental results.Öğe Rule-Based Mamdani-Type Fuzzy Modeling of Heating and Cooling Performances of Counter Flow Ranque-Hilsch Vortex Tubes with Different Geometric Construction for Brass(Trans Tech Publications Ltd, 2013) Ozen, Dilek Nur; Berber, Adnan; Dincer, KevserIn this study, thermal performances of counter flow Ranque-Hilsch vortex tubes were experimentally investigated and modeled with a Rule Based Mamdani-Type Fuzzy (RBMTF) modeling technique. The vortex tubes were made of brass. Diameter of vortex tube (D) was 10 mm. Length of vortex tube (L) was 10D, 11D, 12D, 13D, 14D. Input parameters (xi, L/D) and output parameters (Delta T-h, Delta T-c) were described by RBMTF if-then rules. 45 experimental data sets were used in the training step. R-2 for the Delta T-h was found to be 99.42 % and R-2 for the Delta T-c was 99.66 %. The actual values and RBMTF results demonstrated that RBMTF can be successfully used for the determination of heating and cooling performances of counter flow RHVT with different geometric constructions for brass.Öğe Rule-based Mamdani-type fuzzy modeling of heating and cooling performances of counter-flow Ranque-Hilsch vortex tubes with different geometric construction for steel(Pergamon-Elsevier Science Ltd, 2013) Berber, Adnan; Dincer, Kevser; Yilmaz, Yusuf; Ozen, Dilek NurIn this study, heating and cooling performances of counter-flow Ranque-Hilsch vortex tubes (RHVT) were experimentally investigated and modeled with a RBMTF (Rule-Based Mamdani-Type Fuzzy) modeling technique. Input parameters (xi, L/D) and output parameters Delta T-h, Delta T-c were described by RBMTF if-then rules. 81 experimental data sets were used in the training step. Numerical parameters of input and output variables were fuzzificated as linguistic variables: Very Very Low (L1), Very Low (L2), Low (L3), Negative Medium (L4), Medium (L5), Positive Medium (L6), High (L7), Very High (L8) and Very Very High (L9) linguistic classes. R-2 for the Delta T-h was found to be 99.60% and R-2 for the Delta T-c was 99.80%. The actual values and RBMTF results indicated that RBMTF can be successfully used for the determination of heating and cooling performances of counter-flow RHVT with different geometric constructions for steel. (C) 2013 Elsevier Ltd. All rights reserved.
