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    ANALYSIS OF MAGNETIC PERFORMANCE FOR MAGNETIZED PACKED AND UNPACKED BED
    (Yildiz Technical Univ, 2019) Yildiz, Zehra
    In this study, optimal levels of the magnetized packed bed design parameters on the magnetic performance have been obtained by using Taguchi experimental design approach. Given the associated the parameters such as the diameter of the bed elements (d), magnetic strength (H), and the bed length (L), the results estimate the effects on the magnetizing performance of the magnetized packed bed. The analysis of Taguchi method reveals that, magnetic strength and the diameter of the bed elements have significantly affected the magnetizing performance of the magnetized packed bed. Data obtained from Taguchi experimental design on the magnetic intensity of the bed resulted in the optimized process conditions of 280 kA/m as the magnetic strength, the bed length of 6 cm and the diameter of the bed elements 8 mm. Maximum magnetic intensity 0.606 T was obtained at the optimized conditions in the bed parameters. In addition, magnetic intensity values that called as magnetic performance values are corrected by the uncertainty analyses. Magnetic intensity in the magnetized packed bed adjusted with ASME PTC 19.1 uncertainty analysis methods. Although some partial fluctuations in the magnetic intensity are available as long as the bed, the general variation characteristics of magnetic characteristic property of the bed is constant.
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    APPLICATION OF SIMULATED ANNEALING ALGORITHM FOR THE MAGNETIC FILTRATION PROCESS
    (Yildiz Technical Univ, 2019) Yildiz, Zehra; Yuceer, Mehmet
    The optimization of the magnetic filtration processes parameters on the separation performance of corrosion particles from waste-water suspensions by magnetic filter have been discussed. By using the magnetic filter performance formulas presented in the literature, a base model for magnetic filter performance is selected and the magnetic filter cleaning coefficient is optimized by changing several selected filter process parameters. The magnetic field intensity, diameter of the matrix elements (balls), filter length and filtration velocity are chosen as the inputs parameters and cleaning coefficient as output parameter. The Simulated Annealing (SA) Algorithm was applied to the model. Four variables were successfully optimized.
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    Optimization of Drying Conditions of Kiwi Rings with Osmo-solar Dehydration
    (Univ Namik Kemal, 2023) Yildiz, Zehra; Gencer, Furkan Sabri
    It is the oldest and most common traditional food preservation method known to dry by laying food products under the sun. However, if the food product is in direct contact with the sun light, there is a decrease in the color and nutrient values of the product. To solve these problems, solar dryers have been developed which can be utilized due to indirectly the effect of the sun. In this study, kiwi rings were dried by using osmosolar dehydration as a combination of osmotic dehydration and solar drying. Kiwi rings were first immersed in sucrose solutions and then dried in a solar dryer. Response Surface Methodology used to determine effects of the conditions ondrying performance and find out optimum levels drying conditions for the responses to a safe level. In the response surface method, the drying conditions were selected as the kiwi slice thickness (A), sucrose concentrations (B), immersed time (C) and solar drying time (D). The response to be optimized was chosen as water loss, diameter shrinkage ratio and greenness (a) color change. A successful mathematical model was obtained by the response surface method between the drying conditions and the responses. The suitable model is chosen quadratic for water loss, 2FI model for color change model and shrinkage ratio. The model R-2 value is 0.952 for water loss, 0.737 for a color change and 0.856 for shrinkage ratio. The regression coefficients, along with the corresponding P-values, for the model of production water loss, a color change and shrinkage ratio are described by ANOVA. Values of Prob>F less than 0.0500 indicate model terms are significant. In this case B, C, C-2 are significant model terms for water loss. A, B, C, AB, AC, AD, BC and CD are significant model terms for color change and B, C, AC, AD, BD, CD are significant model terms for shrinkage ratio. The optimum drying conditions levels was determined to sucrose concentration 12.7 %w/v, ring slice thickness 4.06 mm, solar drying time 125 min and immersed time 70.9 min, respectively. In addition, pretreatment of osmotic dehydration was found to be effective in drying kiwi rings with solar tray dryer.
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    Optimizing Drying Conditions of Lemon Rings Combined with Microwave Drying and Osmotic Dehydration
    (Univ Namik Kemal, 2023) Yildiz, Zehra; Reyhan, Suleyman
    In order to shorten the drying time and improve product quality characteristics, with together osmotic dehydration pretreatment and many drying techniques have been used, and the combination of microwave drying and osmotic drying is one of these methods. Drying by using microwave drying and osmotic dehydration process together helps to reduce the negative effects of microwave drying. In this study, microwave oven optimum drying conditions were determined by Response Surface Method after osmotic dehydration pre-drying apply of lemon rings. In the Response Surface Method, drying parameters were chosen as osmotic dehydration time, solution concentration, microwave drying time and microwave power. The responses to be optimized were determined as moisture loss, diametrical shrinkage rate and b color value change. For four factor and three levels, 29 experiments determined according to Box-Behnken design were conducted and the answers were received. Box-Benchken experimental design method with four factors and three levels, A osmotic dehydration drying time (60-180 min), B solution concentration (10-20% (w:v)) was applied in the range of drying time (2-6 min) in C microwave dryer and drying power (100-300 W) in D microwave dryer. The obtained data were analyzed by ANOVA and it was determined that the quadratic models were suitable with 0.9853 for moisture loss, 0.9861 for diametrical shrinkage ratio and 0.9770 for b color value change, which gave the highest R2 values. It was observed that the effects of C, D, CD, A(2), C-2 and D-2 variables on the moisture loss, A, C, D, D-2 variables on diametrical shrinkage rate and A, C, D, A(2) variables on b color value change. Drying parameters were found to be optimum variable levels, osmotic dehydration time was 120 min, solution concentration was 15%, microwave drying time was 4 min and microwave drying power was 200 W.
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    The Prediction of Drying Performance of Banana Rings Dried By Osmo-solar Dehydration Method
    (Univ Namik Kemal, 2022) Yildiz, Zehra; Alcan, Veysel
    Solar drying is known as the oldest and most common traditional food preservation method. However, if the product is indirectly contacted with the sun light, there is negative effect in the color and nutrient values of the product. Solar dryers have been developed to utilize the heat effect of the sun to solve these problems. It can be used in combination with osmotic dehydration to increase the efficiency of the solar drying process. Osmotic dehydration is applied as a pretreatment technique in the drying process. The pretreatments to be applied before drying have important effects on the quality and operating cost of the product to be dried. In addition, the osmotic dehydration pretreatment enables to shorten the drying time and increase the drying potential. In this study, bananas with high drying temperature and high moisture content were sliced into 3 mm rings, then osmotic dehydration pre-drying was applied, and then they were dried in a solar tray dryer. Sucrose and citric acid solution in 2.5%, 5%, 7.5% and 10% (w/v) concentrations were used for osmotic dehydration treatment. In addition, samples without osmotic dehydration were dried in a solar dryer to determine the effect of pretreatment. The input variables of the drying process are solution concentration (0%, 2.5%, 5%, 7.5% and 10%), type of solution (sucrose solution and citric acid solution), osmotic dehydration time (10, 30, 60 and 90 min) and sun drying time (60, 120, 180, 240 and 300 min). Output variables were chosen as moisture ratio and shrinkage rate. The results clearly showed that both the moisture ratio and the shrinkage ratio have increased due to increased solar dryer time. solution concentration and immerse time. Osmotic dehydration was found to be effective in dried banana rings in the solar tray dryer. Gradient Boosting Machine (GBM) was used to model the drying conditions and the model was successful. The correlation coefficient (R-2) values of the GBM model were respectively found as 0.94 and 0.83 for the moisture ratio and the shrinkage ratio.