In situ rumen degradation and in vitro gas production of some selected grains from Turkey

An investigation of the dry matter degradability (DMD) and effective dry matter degradability (EDDM) was performed for barley, wheat, rye, corn, triticale and oat samples, using the Nylon-bag technique. Gas production (GP), metabolizable energy (ME) and in vitro organic matter digestibility (IVOMD) were also studied by using Hohenheim gas test. The DM from barley, wheat, rye and triticale was digested rapidly in the rumen, and, at the 48 h of incubation, degradability was found to be approximately about 80%. The higher degradability observed for these grains than for oats and corn was attributable to the structure of these grains. In contrast, DM of corn and oats was degraded very slowly and reached 66.7 and 66.5 at 48 h, respectively. Effective degradability values of barley, wheat, rye, corn, triticale and oats were determined to be 61.4, 69.0, 64.0, 41.7, 66.7 and 58.6% in 5% rumen outflow rate, respectively. At the end of the 48 h incubation, total gas productions in barley, wheat, rye, corn, triticale and oats were estimated to be 83.6, 87.2, 87.5, 83.5, 85.8 and 63.9 ml/200 mg DM, respectively. The mean ME values of these grains calculated from cumulative gas amount at 24 h incubation were 11.8, 12.1, 12.3, 10.9, 12.4 and 10.2 MJ/kg DM, respectively. In vitro digestible organic matter of barley, wheat, rye, corn, triticale and oats were estimated to be 85.0, 87.3, 88.2, 79.5, 89.0 and 72.6%. Percentage overall EDDM (k=5%) of barley, wheat, rye, triticale and oats was positively correlated with in vitro GP at 6 h, cumulative GP at 24 h and total GP at 48 h (p<0.05). As a result, in situ dry matter degradation of grains showed great differences depending on the chemical compositions. In situ EDDM of grains may be predicted from in vitro gas production parameters.     

The Unloading Effect of Rock Samples and the Quality Evaluation of Engineering Rock Masses

For most evaluating methods of engineering rock mass, the integrality index is an important assessment factor. However, sometimes the value of integrality index would be more than 1.0 because of unloading effect of rock samples and differentia of frequency between the measurements of rock samples and rock mass. In order to solve this problem, unloading index and frequency correcting coefficient were put forward to revise the integrality index. Moreover, the BQ evaluating method proposed in the national standard (GB 50218-94) was improved with the revised method. With the case study of the project of water sealed underground oil tank in Huangdao, it was found that the quality of rock mass in the site was grade I or II.     

A New Beam Column Element of Space Framed Structures for Nonlinear Analysis of Geometric Material

An incremental virtual work equation of three dimensional(3D) beam column element is proposed based on the UL method. The geometric nonlinear tangent stiffness matrix for 3D beam column element is deduced with the consideration of warping, shear deformation and effects of moment spatial rotation. Material nonlinearity is addressed by introducing plastic hinges at the element ends. And the Orbison sectional strength is modified in order to consider the effects of torsion moment and warping. The elastic plastic tangent stiffness matrix is acquired as the element ends are in plastic phase based on the flow theory. With a case studied, it is shown that the model can be used to predict accurately the ultimate bearing capacity and instability mode of 3Dspace frames by only one or two elements, and address the effects of warping and shear deformations effectively.     

Mechanism on Hot Mix Asphalt Construction under Low Temperature Condition

In order to explore the mechanism of low temperature construction and influence of additives on the high temperature performance of the asphalt concrete pavement, the viscosity at 110 ℃, 120 ℃ and 135 ℃ and softening point were measured for SBS modified asphalt and base asphalt with different additive content of ADZ, ADW or ADS, respectively. The additives can reduce viscosity of asphalt and realize construction of asphalt concrete in low temperature. The experimental results showed that: To some extent, three kinds of additives can reduce the viscosity of base asphalt or SBS modified bitumen. In contrast, at lower temperature (120 ℃or 110 ℃), the viscosity of SBS modified asphalt and base asphalt with ADW or ADS were obvious smaller than that of ADZ. With the increase of the three types of additive content, the softening points of base asphalt also increased. However, the softening points of SBS modified asphalt with lower additive content of ADZ, ADW or ADS were smaller than those without ADZ, ADW or ADS.     

Plastic upper bound theory reliability analysis of coal gangue hills

We established the plasticity limit analysis reliability limit state equation and the reliability calculating formula for gangue hills using the JC method. This work was based on the plasticity mechanics limit analysis upper bound theory and traditional slice methods. A reliability index of gangue hill stability was derived using this equation. It was found that the safety coefficient of gangue hills derived by the limit state equation risks failure if the variability of cohesion and internal friction angle are not considered. When the variability of the strength parameters rises, the reliability theory more consistently projects practicality than the limit state equation for gangue hill stability assessment.