Sirvi Autor "Herak, D." järgi

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3D image analysis of the shapes and dimensions of several tropical fruits
(2018) Herak, D.; Mizera, C.; Hrabe, P.; Kabutey, A.
T hree dimension virtual models of Avocado ( Persea americana ) , Salak ( Salacca zalacca ) , Dragon fruit ( Hylocereus undatus ) , Mango ( Mangifera indica ) , Coconut ( Cocos nucifera ) using 3D scanner Intel RealSense were determined. C alculated models based on arithmetic and geometric diameter were also determined. From statistically analysis implies that virtual models on significance level 0 .05 are significantly different with calculated values based on arithmetic or geometric diameter.
Linear compression behaviour of oil palm empty fruit bunches
(2021) Saller, T.; Herak, D.; Mizera, C.; Kabutey, A.
The study describes the mechanical behaviour of oil palm empty fruit bunches (EFB) as a promising product for pyrolysis production. The EFB samples mixture of moisture content 6.3 ± 0.3 (% d.b.) were grouped into different fraction sizes of 10, 20, 40 and 100 mm. The initial pressing height of each fraction size was measured at 60 mm and compressed at a maximum force of 4,500 N and speed of 10 mm min-1 to obtain the force-deformation dependencies using the universal compression machine and pressing vessel of diameter 60 mm with a plunger. Deformation, deformation energy, volume energy and strain were calculated. While deformation decreased with fraction sizes, deformation energy increased. The deformation energies at fraction sizes from 10 mm to 100 mm indicated energy savings of approximately 23%. The optimal fraction size in relation to energy efficiency was observed at 10 mm. The tangent model accurately described the mechanical behaviour of the EFB samples mixture. The results provide useful information for the design of optimal technology for processing EFB for energy purposes.
Mathematical description of loading curves and deformation energy of bulk oil palm kernels
(2018) Kabutey, A.; Herak, D.; Mizera, C.; Hrabe, P.
The study aimed at describing the experimental and theoretical relationships between t he force and deformation curves as well as the deformation energy of bulk oil palm kernels under compression loading. V essel diameters of 60, 80 and 100 mm with initial pressing heights of the bulk kernels measured at 40, 60 and 80 mm were examined by appl ying a maximum compressive force of 200 kN and a speed of 5 mm min - 1 . For the theoretical description of the force and deformation curves, the tangent curve mathematical model was applied using the MathCAD 14 software where the force coefficient of mechani cal behaviour, A (kN), the deformation coefficient of mechanical behaviour, B (mm - 1 ) and the fitting curve function exponent, n ( - ) were determined respectively. The determined coefficients in addition to the maximum deformation values obtained from the co mpression test were used for the estimation of the theoretical or analytical deformation energy. The determined regression models expressing the deformation, numerical energy and theoretical energy as well as the tangent model coefficients A and B dependen t on the vessel diameter and pressing height were statistically significant ( P < 0.05) or ( F - ratio > F - critical) . Improving the mechanical pressing of oil extraction for both domestic and industrial applications still remain a concer n of researchers and en gineers.
Theoretical analysis of force, pressure and energy distributions of bulk oil palm kernels along the screwline of a mechanical screw press FL 200
(2019) Kabutey, A.; Herak, D.; Mizera, C.; Hrabe, P.
The present study is a follow-up of the previously published study on the mathematical description of loading curves and deformation energy of bulk oil palm kernels under compression loading, aimed at determining theoretically the amounts of force, pressure and energy along the screw lamella positions 𝑆𝐿𝑝 of the screw press FL 200 by applying the tangent curve mathematical model and the screwline geometry parameters (screw shaft diameter, screw inner and outer diameters, screw pitch diameter and the screw thickness). The fitting curve value 𝐹𝑣 of the tangent mathematical model was further examined at 𝐹𝑣 = 2 and 𝐹𝑣 = 3 by identifying the force, deformation, stress and compression coefficients at varying vessel diameters 𝐷𝑣 and initial pressing heights 𝐻𝑡 of the bulk oil palm kernels. Based on the results of the stepwise regression analysis, the amounts of the theoretical deformation energy 𝑇𝐷𝐸 in linear pressing as well as the theoretical force 𝐹𝑟 , pressure 𝑃𝑟 and energy 𝑆𝐿𝐸 of the screw press FL 200 were statistically significant (P-value < 0.05) or (F-value > significance F) in relation to the predictors (𝐻𝑡 , 𝐷𝑣 , 𝐹𝑣 and 𝑆𝐿𝑝). The coefficient of determination (R2 ) values between 61 and 86 % were observed for the determined regression models indicating that the responses 𝑇𝐷𝐸, 𝐹𝑟 , 𝑃𝑟 and 𝑆𝐿𝐸 can accurately be predicted by the corresponding predictors. The normal probability plots of the responses approximately showed a normal distribution.
Utilization of image analysis for description of drying characteristics of selected tropical fruits
(2019) Wasserbauer, M.; Herak, D.; Mizera, C.; Hrabe, P.
This study is focused on the utilization of image analysis for description of dimensions, and colours changes of fruits during drying process. Selected tropical fruits such are banana (Musa acuminata), mango (Magnifera indica) and pineapple (Ananas comosus) originally from North Sumatera in Indonesia were used in this experiment. Sliced pieces of the fruits were dried in experimental oven under temperature 90 °C for period of time 180 min and image of fruits samples were recorded by digital camera with HD resolution continuously throughout drying process. With aid of image analysis using Image J software and regarding to drying characteristics the colours and dimensions of the samples were analysed.

Sirvi Autor "Herak, D." järgi

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