Extraction of oil from rapeseed using duo screw press

ArticleThis study was focused on the analysis of optimize the pressing process of rapeseeds ( B rassica napus L.) using screw press. For pressing of oil a screw press Farmer 20 – duo (Farmer 20, Farmet a.s., Ceska Skalice, Czech republic) was used. The screw rotation speed 10, 20, 30, 40, 55 and 65 rpm was used. Oil recovery efficiency and specific mechanical energy were decreased when the seed material troughput was increased. It has been found that the optimal operation point for screw press Farmer 20 – duo was at 20 kg h - 1 rapeseed throughput. The specific mechanical energy at the optimal operation point was 0.61 kWh kg oil - 1 Maximum oil recovery efficiency 82.6% was found at the lowest screw speed

Mathematical description of loading curves and deformation energy of bulk oil palm kernels

ArticleThe 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

Mechanical behaviour of Sugar palm (Arenga pinnata) fibres

ArticleThe tensile strength of Sugar palm ( Arenga pinnata ) fibres was examined. Fibre samples were prepared and tested up to the point of rupture with a deformation rate of 0.05 min - 1 . The tensile device (Labortech, MPTest 5.050, Czech Republic) were used to determine the tensile force. The aim of the paper was to describe a mechanical behaviour of Sugar palm ( Arenga pinnata ) fibres. Measured values can be used as a basis for further research on the application of Sugar palm fibres

Theoretical analysis of force, pressure and energy distributions of bulk oil palm kernels along the screwline of a mechanical screw press FL 200

ArticleThe 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 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 of the tangent mathematical model was further examined at = 2 and = 3 by identifying the force, deformation, stress and compression coefficients at varying vessel diameters and initial pressing heights of the bulk oil palm kernels. Based on the results of the stepwise regression analysis, the amounts of the theoretical deformation energy in linear pressing as well as the theoretical force , pressure and energy of the screw press FL 200 were statistically significant (P-value significance F) in relation to the predictors ( , , and ). The coefficient of determination (R2 ) values between 61 and 86 % were observed for the determined regression models indicating that the responses , , and can accurately be predicted by the corresponding predictors. The normal probability plots of the responses approximately showed a normal distribution

3D image analysis of the shapes and dimensions of several tropical fruits

ArticleT 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

Received: January 29th, 2021 ; Accepted: April 8th, 2021 ; Published: May 20th, 2021 ; Correspondence: [email protected] 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

Modelling of hot-air and vacuum drying of persimmon fruit (Diospyros kaki) using computational intelligence methods

The study evaluated the feasibility of applying computational intelligence methods as a non-destructive technique in describing the drying behaviour of persimmon fruit using vacuum drying (VD) and hot-air-drying (HAD) methods and to compare the results with thin layer mathematical models. Drying temperatures were 50, 60 and 70 °C. Kinetic models were developed using semi-theoretical thin layer models and computational intelligence methods: multi-layer feed-forward artificial neural network (ANN) and support vector regression (SVR). The statistical indicators of coefficient of determination (R2 ) and root mean square error (RMSE) were used to assess the suitability of the models. The thin-layer mathematical models namely page and logarithmic accurately described the drying kinetics of persimmon slices with the highest R2 of 0.9999 and lowest RMSE of 0.0031. ANN showed R2 and RMSE values of 1.0000 and 0.0003, while SVR showed R2 of 0.9999 and RMSE of 0.0004. The validation results indicated good agreement between the predicted values obtained from the computational intelligence methods and the experimental moisture ratio data. Based on the study results, computational intelligence methods can reliably be used to describe the drying process of persimmon fruit

The effects of temperature on the kinetics of aluminium evaporation from the Ti-6Al-4V alloy

In the paper, results of the study on temperature effects on the rate of aluminium evaporation from the Ti-6Al-4V alloy during smelting in a vacuum induction furnace are presented. During smelting at 1 973 – 2 023 K, 10 Pa and 100 Pa, up to 26 % reduction in the aluminium content in the alloy compared to the initial value is observed. The determined values of overall mass transport coefficient are 1,48∙10-5 m∙s sup>-1 – 1,95∙10 sup>-5m∙s sup>-1

Mutational pathway determines whether drug gradients accelerate evolution of drug-resistant cells

Drug gradients are believed to play an important role in the evolution of bacteria resistant to antibiotics and tumors resistant to anti-cancer drugs. We use a statistical physics model to study the evolution of a population of malignant cells exposed to drug gradients, where drug resistance emerges via a mutational pathway involving multiple mutations. We show that a non-uniform drug distribution has the potential to accelerate the emergence of resistance when the mutational pathway involves a long sequence of mutants with increasing resistance, but if the pathway is short or crosses a fitness valley, the evolution of resistance may actually be slowed down by drug gradients. These predictions can be verified experimentally, and may help to improve strategies for combatting the emergence of resistance.Comment: 6 pages, 3 figures, final version before acceptance to Phys. Rev. Letters. P.G and B.W contributed equally to this wor