Mechanical Properties Of Grains Research Articles

Some physical and mechanical properties of roasted Zerun wheat

Some physical and mechanical properties of roasted Zerun wheat were investigated in the moisture range from 8.80% to 23.40% wet basis. Mechanical properties were evaluated by examining the effect of moisture content upon the grain rupture force, energy and Weibull parameters. Length, width, thickness, porosity and angle of repose increased nonlinearly from 6.09 to 6.36mm; 4.17 to 4.18mm; 2.66 to 2.78mm; 37.71% to 39.09% and 33.02° to 37.90°, respectively when moisture content increased. The Weibull distribution fits the data for rupture force and energy. The Weibull modulus and scale parameter for rupture force varied between 3.88 and 6.20; 26.61 and 44.24N, respectively. The Weibull modulus for energy increased from 2.15 to 3.24 with increased in moisture content. Measured mechanical properties of grains showed that the brittleness and fragile structure of the roasted grain gradually lost its characteristic crispiness and become soft and ductile above 13.78% moisture content.

The Moisture Content Effect on Some Physical and Mechanical Properties of Corn (Sc 704)

Physical and mechanical properties of grains are necessary for the designing the facility of storage, handling and processing of agricultural products. Physical and mechanical properties of corn grains were determined as a function of moisture content in the range of 4.73-22% w.b. (wet basis) using standard techniques. The average length, width, thickness, geometric mean diameter, equivalent diameter, arithmetic diameter, sphericity, angle of repose, grain volume, surface area and aspect ratio ranged from 11.62 to 12.60 mm, 7.27 to 7.98 mm, 4.47 to 4.71 mm, 7.20 to 7.77 mm and 7.63 to 7.96 mm, 7.77 to 8.43 mm, 62.31% to 62.00%, 49° to 58°, 209.66 to 265.00 mm3, 137.69 to 160.09 mm2 and 63.05% to 63.77% as the moisture content increased from 4.73-22% w.b. With increase in moisture content, the bulk density was found to decrease from 710 to 649 kgm-3 whereas true density and porosity increased from 1250 to 1325 kgm-3 and 43.2% to 51.02%. In the moisture range from 4.73% to 22% w.b., studies on rewetted corn grains showed that the thousand grain weight (TGW) increased linearly from 271.0 to 321.4 g. The static coefficient of friction of corn grains increased linearly against surfaces of three materials, namely, plastic (0.32–0.51), plywood (0.48–0.60) and galvanized iron (0.38–0.65) and the static angle of repose increased from 49º to 58º when the moisture content increased from 4.73% to 22% w.b. The mechanical properties of corn were determined in terms of average rupture force and rupture energy. Rupture energy of the corn grains generally increased in magnitude with an increase in moisture content, while rupture force decreased for compression.

Modeling Effective Moisture Diffusivity of Wheat (Tajan) During Air Drying

Drying conditions can greatly affect the physical and mechanical properties of grains. The drying process must be controlled to reduce or minimize drying damage. In this paper the thin layer drying behavior of wheat (Tajan) in a convective dryer is experimentally investigated. The mathematical modeling by using thin layer kinetics drying models available in literature was performed. Drying experiments were conducted at inlet drying air temperatures of 35, 45, 50, 60 and 70°C and at a fixed drying air velocity of 0.3 m/s and initial moisture content of 0.26–0.27 (d.b.). The effects of drying air temperature on the model's parameters were predicted by a linear regression analysis. The constants and coefficients of this model were be explained in terms of drying air temperature. A correlation coefficient (r) of 0.99 was found for the multiple regression model of moisture content during the drying process using different temperature values. Values of the diffusion coefficients for the whole kernel ranged from 2.28 × 10−11 to 1.14 × 10−10 m2/s.

INTERACTION BETWEEN LATTICE AND GRAIN BOUNDARY DISLOCATIONS AND THEIR ROLE IN MECHANICAL PROPERTIES OF INTERFACES

This paper is a brief review of the relationship between the structure and the mechanical properties of grain interfaces. Early work had inferred that such a correlation exists from experiments with bicrystals of different orientations. More recently, the advances in the understanding of grain boundary structure have allowed specifying the structure and then studying how it relates to mechanical behavior. The rudiments of grain boundary structure characterization are discussed. The mechanical properties of interfaces are described in terms of slip induced intergranular cavitation, continuity of slip bands across interfaces and the yield strength of interfaces. The need for much more work in this important area is emphasized.

Mechanical properties of grain oriented piezo -ceramics with bismuth-layer and tungsten-bronze structures

Abstract Grain oriented piezoelectric ceramics with bismuth-layer and tungsten-bronze structures were prepared by hot-pressing. Bend strength measurements in the direction parallel and perpendicular to the hot-pressing direction showed different anisotropic behaviors for SrBi2Nb2O9 and (Pb0.6Ba0.4)0.97La0.02Nb2O6 ceramics. Microindentation technique was applied and fhe crack propagation was examined with fractography.