Yazar "Ertekin, Can" seçeneğine göre listele
Listeleniyor 1 - 8 / 8
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Assessing monthly average solar radiation models: a comparative case study in Turkey(SPRINGER, 2011) Sonmete, Mehmet H.; Ertekin, Can; Menges, Hakan O.; Haciseferogullari, Haydar; Evrendilek, FatihSolar radiation data are required by solar engineers, architects, agriculturists, and hydrologists for many applications such as solar heating, cooking, drying, and interior illumination of buildings. In order to achieve this, numerous empirical models have been developed all over the world to predict solar radiation. The main objective of this study is to examine and compare 147 solar radiation models available in the literature for the prediction of monthly solar radiation at Ankara (Turkey) based on selected statistical measures such as percentage error, mean percentage error, root mean square error, mean bias error, and correlation coefficient. Our results showed that Ball et al. (Agron J 96:391-397, 2004) model and Chen et al. (Energy Convers Manag 47:2859-2866, 2006) model performed best in the estimation of solar radiation on a horizontal surface for Ankara.Öğe The effects of drying parameters on drying characteristics, colorimetric differences, antioxidant capacity and total phenols of sliced kiwifruit(SPRINGER, 2019) Mengeş, Hakan O.; Ünver, Ahmet; Özcan, Mehmet Musa; Ertekin, Can; Sonmete, Mehmet HakanThe influence of drying parameters on drying characteristics, colorimetric differences, antioxidant capacity and total phenols of sliced kiwifruit were researched. The kiwi fruits dried between 2.6h and 12.1h for different drying conditions. Total phenol content of dried fruits were ranged from 2.03-2.71mg GAE/L. Free radical scavenging activity were varied from 26.04% to 40.91%. The effect of different drying temperatures were not very effective on the total phenol content of kiwi fruits. But, the free radical scavenging activity were variable. While L* value were in the range of 51.41 and 72.90, the a* value were ranged between -8.22 and 3.47 and the b* value between 22.24 and 40.37. The most suitable model is Midilli etal. model with low RMSE, reduced chi-square and high modeling efficiency values. While the effective diffusivity ranged between 2.63x10(-10) and 1.29x10(-9)m(2).s(-1), the activation energy was between 28.51 and 34.16kJmol(-1).Öğe Evaluation of Global Solar Radiation Models for Konya, Turkey(Pergamon-Elsevier Science Ltd, 2006) Menges, Hakan Okyay; Ertekin, Can; Sonmete, Mehmet HakanSolar radiation data are required by solar engineers, architects, agriculturists and hydrologists for many applications such as solar heating, cooking, drying and interior illumination of buildings. In order to achieve this, several empirical models have been developed to predicted the solar radiation all over the world. The main objective of this study is to review the global solar radiation models available in the literature. In order to evaluate the applicability of 50 models for computing the monthly average daily global radiation on a horizontal surface, the geographical and meteorological data of Konya, Turkey (37 degrees 52'N latitude, 32 degrees 29'E longitude) was used. The models were compared on the basis of statistical error tests such as the percentage error (e), mean percentage error (MPE), root mean square error (RMSE), mean bias error (MBE), regression coefficient (R) and Nash-Sutcliffe equation (NSE). According to the results, the Ertekin and Yaldiz model showed the best estimation of the global solar radiation on a horizontal surface for Konya, Turkey, by means of the MPE (0.004266%), RMSE (0.022576 MJ/m(2)), MBE (0.000000 MJ/m(2)), R (0.999993) and NSE (0.999985) statistical tests: H = 20.296019 - 0.096134H(0) + 0.3175936 - 0.146422RH + 10.705159 (S/S-0) -0.288332T + 0.021331TS + 0.359791C + 0.207588P - 0.076444E.Öğe Mathematical modeling of thin layer drying of carrot slices by forced convection(SPRINGER, 2017) Sonmete, Mehmet Hakan; Mengeş, Hakan Okyay; Ertekin, Can; Özcan, Mehmet MusaThe aim of this study is to evaluate the effect of drying air temperature, velocity and slice thickness on thin layer drying model of carrot slices. A laboratory dryer was used for thin layer carrot drying process and moisture ratio values (MR) for any drying time were compared using 14 different models, i.e., Newton, Page, Modified Page I and II, Henderson and Pabis, Logarithmic, Two term, Two term exponential, Wang and Singh, Thompson, Diffision approximation, Verma et al., Modified Henderson and Pabis and Midilli et al. models. Root mean square error (RMSE), reduced Chi square (chi(2)) and modeling efficiency (EF) were used as statistical parameters to determine the most suitable model among them. The effects of drying parameters on the best suited drying model coefficients were than determined with linear, logarithmic, power exponential and Arhenius type equations. According to the results, moisture ratio values could be predicted by the Midilli et al. model with high accuracy. It is also possible to predict the moisture content of the product with a generalized model showing the effect of the drying air temperature, velocity and slice thickness with the range of 55-75 degrees C, 2.0-3.0 m s(-1) and 3-9 mm, respectively.Öğe Mathematical modeling of thin layer drying of Golden apples(ELSEVIER SCI LTD, 2006) Menges, Hakan Okyay; Ertekin, CanIn this study, a laboratory dryer was used for thin layer apple drying process and moisture ratio at any, drying time were compared by Newton, Page, Modified Page, Henderson and Pabis. logarithmic, two-term. two-term exponential. Wang and Singh. Thompson, diffusion approximation, Modified Henderson and Pabis, Verma et al. and Midilli et al. models. The effect of drying air temperature and velocity on the coefficients of the best suited moisture ratio model were determined by multiple regression method. Root mean square error (RMSE) and chi-square (chi(2)) were used for the determination of the best suitable model. In addition to these statistical parameter, the modeling efficiency (EF) was also determined. According to the results, Midilli et al. model is superior to the others for explaining drying behavionr of apple. It is possible to predict moisture content of the product with generalised model showing the effect of drying air temperature and velocity on the model constants and coefficients. (c) 2005 Elsevier Ltd. All rights reserved.Öğe Physical and nutritional properties of jujube (Zizyphus jujuba Mill.) growing in Turkey(2008) Akbolat, Davut; Ertekin, Can; Mengeş, Hakan Okyay; Ekinci, Kamil; Erdal, İbrahimSeveral physical and nutritional properties of jujube fruits (Zizyphus jujuba Mill.) grown in Turkey were investigated. These properties are necessary for the design of equipments for harvesting, processing, transportation, sorting, separating and packing. The average fruit length, width, thickness, the geometric mean diameter, sphericity index, fruit mass, thousand of fruit mass and volume of fruit of jujube fruits were determined as 17.75 mm, 14.81 mm, 14.19 mm, 15.43 mm, 87.56 %, 1.26 g, 1139 g and 1.99 cm3, respectively. The bulk density, fruit density and porosity were 380 kg/m 3, 639 kg/m3 and 39.35 %, respectively. The static friction coefficient on galvanized iron sheet, iron sheet, thin plate, wood and rubber were 0.369, 0.528, 0.633, 0.475 and 0.844, the dynamic friction coefficient on the same surfaces were 0.317, 0.475, 0.581, 0.422 and 0.792, respectively. The moisture content, titratable acidity, ascorbic acid, rupture strength and terminal velocity were 20.04 %, 0.33 %, 118.4 mg/100 g fresh weight, 21.49 N/mm2 and 5.44 m/s, respectively. Protein, K, Ca, P, Mg and N amount were 14.13 %, 1.12 %, 0.21 %, 0.12 %, 0.07 % and 2.26 %, respectively.Öğe Physical and nutritional properties of oleaster (Elaeagnus angustifolia L.) growing in Turkey(2008) Akbolat, Davut; Ertekin, Can; Mengeş, Hakan Okyay; Güzel, Emin; Ekinci, KamilSeveral physical and nutritional properties of oleaster fruits (Elaeagnus angustifolia L.) grown in Turkey were investigated. These properties are necessary for the design of equipments for harvesting, processing and transportation, sorting, separating and packing. The average fruit length, width, thickness, the geometric mean diameter, sphericity index, fruit mass, thousand of fruit mass and volume of fruit of oleaster fruits were determined as 25.39 mm, 18.22 mm, 18.27 mm, 20.28 mm, 80.26 %, 2.09 g, 2101.4 g and 4.73 cm3, respectively. The bulk density, fruit density and porosity were 277 kg m-3, 462 kg m-3 and 35.03 %, respectively. While the static friction coefficient on galvanized iron sheet, iron sheet, thin plate, wood and rubber were 0.511, 0.438, 0.292, 0.511 and 0.729, the dynamic friction coefficient on the same surfaces were 0.438, 0.365, 0.219, 0.438 and 0.584, respectively. The moisture content, titrable acidity, ascorbic acid, skin firmness and terminal velocity were 16.91 %, 4.99 %, 4.65 mg 100 g fresh weight-1, 6.65 N mm-2 and 8.26 m s-3, respectively. Protein, K, Ca, P, Mg and N amount were 12.33. 1.10, 0.07, 0.06, 0.05 and 1.97 %, respectively.Öğe Thin layer drying model for treated and untreated Stanley plums(PERGAMON-ELSEVIER SCIENCE LTD, 2006) Menges, Hakan Okyay; Ertekin, CanIn this study, a laboratory dryer was used for thin layer drying of treated and untreated plums, and the moisture ratios at any drying time were compared by 14 different mathematical models. The effect of drying air temperature and velocity on the coefficients of the best suited moisture ratio model were determined by the multiple regression method. Root mean square error (RMSE) and chi-square (chi(2)) were used for determination of the best suitable model. In addition to these statistical parameters, the modeling efficiency (EF) was also determined. According to the results, the Midilli et al. model is superior to the others for explaining the drying behaviour of treated and untreated plums. It is possible to predict the moisture content of the product with a generalised model showing the effect of drying air temperature and velocity with the range of 60-80 degrees C and 1.0-3.0m/s. The effective diffusivity was found to be between 1.197 x 10(-7) and 4.551 x 10(-7) m(2)/s for treated plums and between 1.179 x 10(-9) and 6.671 X 10(-9) m(2)/s for untreated plums. (c) 2005 Elsevier Ltd. All rights reserved.