Physical and mechanical properties of Jatropha curcas L. seeds

Kassahun Solomon Laha

Master's thesis

Fyzikální a mechanické vlastnosti semen Jatropha curcas L.

Abstract:

ABSTRACTThe purpose of this study was to investigate the moisture- dependant physical and mechanical properties of jatropha curcas L seed. And the other aim was to find the optimum moisture content which requires minimum energy. The physical properties investigated include post-harvest moisture content, seed dimensions, sphericity, 1000 seed mass, surface area, volume, bulk density and porosity. The mechanical properties such as rupture force, deformation at rupture point, hardness, energy used for rupture and unit energy were also investigated and reported. To measure each parameter in the laboratory, researcher’s recommended laboratory procedures were seriously followed. And all the above mentioned properties of seeds have been evaluated as a function of moisture content in the range of 7.14–47.83 % w.b. In the moisture range average seeds length, width, thickness, arithmetic mean diameter and geometric mean diameter increased linearly from 17.19 to 19.12mm, 11.03 to 11.41mm, 8.55 to 9.15mm, 12.26 to 13.23mm and 11.74 to 12.59mm respectively as the moisture content increased; while on the contrary sphericity and porosity decreased from 0.68 to 0.66 and 59.70 to 45.85% respectively; the surface area and volume increased from 434.05 to 499.43 mm2 and 594.68 to 719.53mm3 respectively; 1000 seed mass and bulk density increased from 391.29 to 525.80 kg/m3 and 606.06 to 934.78 g respectively. The rupture force and hardness decreased non–linearly from 98.09 to 96.74 kN, and 3.77 to 3.49 kN/mm respectively as the moisture content increased. On the other hand deformation energy, unit energy and maximum deformation increased non–linearly from 328.54 to 415.66 J, 773.26 to 915.91 kJ/m3 and 25.98 to 27.75 mm respectively as the moisture content increased. The optimum moisture content was 17.60% w.b.

Abstract:

ABSTRACTThe purpose of this study was to investigate the moisture- dependant physical and mechanical properties of jatropha curcas L seed. And the other aim was to find the optimum moisture content which requires minimum energy. The physical properties investigated include post-harvest moisture content, seed dimensions, sphericity, 1000 seed mass, surface area, volume, bulk density and porosity. The mechanical properties such as rupture force, deformation at rupture point, hardness, energy used for rupture and unit energy were also investigated and reported. To measure each parameter in the laboratory, researcher’s recommended laboratory procedures were seriously followed. And all the above mentioned properties of seeds have been evaluated as a function of moisture content in the range of 7.14–47.83 % w.b. In the moisture range average seeds length, width, thickness, arithmetic mean diameter and geometric mean diameter increased linearly from 17.19 to 19.12mm, 11.03 to 11.41mm, 8.55 to 9.15mm, 12.26 to 13.23mm and 11.74 to 12.59mm respectively as the moisture content increased; while on the contrary sphericity and porosity decreased from 0.68 to 0.66 and 59.70 to 45.85% respectively; the surface area and volume increased from 434.05 to 499.43 mm2 and 594.68 to 719.53mm3 respectively; 1000 seed mass and bulk density increased from 391.29 to 525.80 kg/m3 and 606.06 to 934.78 g respectively. The rupture force and hardness decreased non–linearly from 98.09 to 96.74 kN, and 3.77 to 3.49 kN/mm respectively as the moisture content increased. On the other hand deformation energy, unit energy and maximum deformation increased non–linearly from 328.54 to 415.66 J, 773.26 to 915.91 kJ/m3 and 25.98 to 27.75 mm respectively as the moisture content increased. The optimum moisture content was 17.60% w.b.

Keywords

Keywords, compression, deformation, jatropha curcas (jatropha), wet basis (w.b), total energy

Keywords

Keywords, compression, deformation, jatropha curcas (jatropha), wet basis (w.b), total energy

Language used: English

Date on which the thesis was submitted / produced: 7. 4. 2011

Thesis defence

• Supervisor: doc. Ing. David Herák, Ph.D.

Czech University of Life Sciences Prague

Faculty of Engineering

Master programme:
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