Tag Archives: strain

xxx V. Kažimírová, Ľ. Kubík, J. Chrastina and T. Giertl
Determination of mechanical properties of poppy waste pellets
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Determination of mechanical properties of poppy waste pellets

V. Kažimírová¹*, Ľ. Kubík², J. Chrastina¹ and T. Giertl³

¹Slovak University of Agriculture in Nitra, Faculty of Engineering, Department of Building Equipment and Technology Safety, Tr.A. Hlinku 2, SK949 76 Nitra, Slovak Republic
²Slovak University of Agriculture in Nitra, Faculty of Engineering, Department of Physics, Tr.A. Hlinku 2, SK949 76 Nitra, Slovak Republic
³Slovak University of Agriculture in Nitra, Faculty of European Studies and Regional Development, Department of Regional Bioenergy, Tr.A. Hlinku 2, SK949 76 Nitra, Slovak Republic
*Correspondence: viera.kazimirova@uniag.sk

Abstract:

The work deals with evaluation of mechanical properties three types of pellet samples produced from poppy waste. The pellets were submitted to compressive loading. The compressive loading curves of dependencies of force on strain and force on time were realised. Certain mechanical parameters were determined, namely the diameter of the sample, length of the sample, force at 10% of strain, force in the first maximum of the force – strain curve, strain in the first maximum of the force – strain curve, modulus of elasticity, force in the inflex point of the force – time and force – strain curves and strain and stress in the inflex point of the force – time and force – strain curves. The work lists correlations of mechanical parameters of individual pellet types. The pellet type 1 made only of ground poppy head mass has shown the best results, the pellet type 3 consisting of ground poppy heads after harvest and waste from sieving of poppy seeds in mass proportion 1 : 1 has shown the worst results.

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941–951 O.L. Akangbe and D. Herak
Mechanical behaviour of selected bulk oilseeds under compression loading
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Mechanical behaviour of selected bulk oilseeds under compression loading

O.L. Akangbe and D. Herak*

Czech University of Life Sciences, Faculty of Engineering, Department of Mechanical Engineering, Kamycka 129, Praha 6 – Suchdol, CZ16521 Prague, Czech Republic
*Correspondence: herak@tf.czu.cz

Abstract:

Cold pressing or compressive mechanical expression of oil from bulk oilseeds without thermal treatments or appreciable thermal effects facilitates the preservation of quality in expressed oils and enhances their stability in storage. Mechanical response of bulk oilseeds during cold expression which are vital to equipment design vary with crops and are not completely understood. Mechanical behaviours of bulk seeds of camelina, pumpkin and sesame relevant to cold pressing were investigated at moisture contents of 7.04, 8.60 and 6.06% (d.b.), 80 mm pressing depth and a compressive force of 100 kN, applied uniformly at 10 mm min-1. Deformation varied with incremental force and among crops at peak compression. Deformations in Camelina, Sesame and Pumpkin seeds were 40.2, 41.6 and 50.9 mm at peak compression. Oil point pressures of Sesame, Camelina and Pumpkin seeds were 3.83, 7.49 and 8.83 MPa, respectively. Oil recovery at the applied load was similar in Camelina and Sesame but significantly lower in pumpkin seeds. Volume energy requirement for the expression of oil from camelina, pumpkin and sesame seeds were 2.56, 1.72 and 1.46 MJ m-3, respectively. An assessment of the pressed cake after oil expression revealed that the materials were capable of further deformation under compression.

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939-947 D. Herak
Analysis of mechanical behaviour of Jatropha curcas L. bulk seeds under compression loading with aid of reciprocal slope transformation method and tangent curve method
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Analysis of mechanical behaviour of Jatropha curcas L. bulk seeds under compression loading with aid of reciprocal slope transformation method and tangent curve method

D. Herak

Czech University of Life Sciences Prague, Faculty of Engineering, Department of Mechanical Engineering, Kamycka 129, 16521, Prague, Czech Republic; e-mail: herak@tf.czu.cz

Abstract:

This study is focused on the utilization of the reciprocal slope transformation method (RST) and tangent curve method (TCM) for description of mechanical behaviour of Jatropha bulk seeds under compression loading. The experimental data derived from a compression test was done using compression device and pressing vessel with diameter 60 mm at compression speed of 1 mm s−1 and compressive force between 0 kN and 100 kN. Measured dependency between compressive force and deformation was fitted by RST method and TCM method and they were statistically analysed by ANOVA. Comparison of both methods in individual pressing regions is an integral part of this manuscript. It was determined that reciprocal slope transformation method describes precisely the beginning of deformation characteristics and it can cover the reorganizing process in the bulk seeds. From the conducted study it also follows that tangent curve method is suitable for description of mechanical behaviour at bulk deformations in which the reorganization process in the bulk seeds is finished yet.

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