Note On Certain Inequalities for Neuman Means

In this paper, we give the explicit formulas for the Neuman means $N_{AH}$, $N_{HA}$, $N_{AC}$ and $N_{CA}$, and present the best possible upper and lower bounds for theses means in terms of the combinations of harmonic mean $H$, arithmetic mean $A$ and contraharmonic mean $C$.Comment: 9 page

The Effects Of Surface Characteristics On Liquid Behaviors Of Fins During Frosting And Defrosting Processes

Liquid behaviors, including droplet condensation and frost melt water retention, of fins during frosting and defrosting processes on three aluminum fins with different surface characteristics under winter operating conditions of an air source heat pump were investigated. The effects of the surface characteristics, including the contact angle and the contact angle hysteresis, were analyzed. Droplets were observed firstly on a bare fin and on a super hydrophobic fin last, and exhibited different sizes and shapes under the effects of the surface characteristics. The droplet distribution was sparser on the super hydrophobic fin than on the other two fins because of the consolidation, rolling and departure of droplets. There was an obvious difference on frost melt water retention between the three fins. Residual water formed a thin water film on a hydrophilic fin, while only a few spherical droplets of small sizes stayed on the super hydrophobic fin. The effects of the surface characteristics were found to be significant on the mass of residual water, which decreased by 79.82% on the super hydrophobic fin compared with that on the hydrophilic fin. Finally, the effects of the contact angle and the contact angle hysteresis on frost melt water retention were quantitatively analyzed. Results indicate that the super hydrophobic fin can restrain the droplet condensation and frost melt water retention

Study on Roadway Parameters of Broken Compound Roof of Gently Inclined Thick Coal Seam

AbstractThis paper through investigation of the geological conditions of Da’ Anshan's coal mine, according to the special of the broken compound roof on inclined thick coal seam, select the anchor suspension theory and composite beam theory, design the roadway support's anchor parameters, and apply the finite element software ADINA carry out simulation analysis, through the contrast of analysis and engineering data, proved that the design of support parameters is reasonably and practicable. The research has practical value and can guide similar projects

Several Treatments on Nonconforming Element Failed in the Strict Patch Test

For nonconforming finite elements, it has been proved that the models whose convergence is controlled only by the weak form of patch tests will exhibit much better performance in complicated stress states than those which can pass the strict patch tests. However, just because the former cannot provide the exact solutions for the patch tests of constant stress states with a very coarse mesh (strict patch test), their usability is doubted by many researchers. In this paper, the non-conforming plane 4-node membrane element AGQ6-I, which was formulated by the quadrilateral area coordinate method and cannot pass the strict patch tests, was modified by three different techniques, including the special numerical integration scheme, the constant stress multiplier method, and the orthogonal condition of energy. Three resulting new elements, denoted by AGQ6M-I, AGQ6M-II, and AGQ6M, can pass the strict patch test. And among them, element AGQ6M is the best one. The original model AGQ6-I and the new model AGQ6M can be treated as the replacements of the well-known models Q6 and QM6, respectively