Elastic Constants and Thermodynamic Properties of Cu, Cu2O and CuO from First-Principles Calculations

Elastic constants and some thermodynamic properties of Cu and copper oxides were studied by first-principles total energy calculations. The elastic constants of Cu and copper oxides were calculated on pressure. It was shown that the calculated elastic constants of Cu, Cu2O and CuO at zero pressure were well consistent with previous experimental data. The specific heat capacities and thermal expansion coefficient of Cu and copper oxides were successfully obtained. The calculated specific heat capacities of Cu were well consistent with the previous experimental data.

Centreline velocity decay measurements in low-velocity axisymmetric jets

The streamwise velocity profiles of low-velocity isothermal axisymmetric jets from nozzles of different diameters were measured and compared with previous experimental data. The objective of the measurements was to examine the dependence of the diffusion of the jet on the outlet conditions. As the outlet velocity was decreased, the centreline velocity decay coefficient began to decrease at an outlet velocity of about 6 m s−1.

Characteristic Recovery Time of an Erythrocyte From an Extensional Deformation

An analytical expression for the characteristic recovery time of an erythrocyte subject to an extensional deformation is derived using a previous nonlinear Kelvin-Voigt model. The recovery time thus obtained depends on the initial deformation in agreement with experimental observations, as a result of the nonlinearity of the model. The validity of the analytical results is confirmed using previous experimental data.

Application of Dressler Theory to Weir Flow

The curvilinear flow past a circular-crested weir is analyzed with the help of Dressier equations. Specifically, the lower range of the depth over the weir crest is considered in the analysis, so that the shallow depth model could be adopted. The weir discharge coefficient is determined as a function of the total head of the approach flow and the crest radius. The weir discharge coefficient obtained on the basis of Dressier theory is verified with the help of present and previous experimental data.

Multishock Compactions of Powder Media Influenced by Elastic Waves in Punch and Plug

The previous theoretical predictions of the compaction of a copper powder medium, based on the assumption that the punch and plug were both a rigid body, did not satisfactorily agree with the experimental results obtained for short initial powder lengths and long plug lengths. This type of compaction amounts to cases when the plug length exceeds the second critical length which will be described below. Shock waves in a powder medium and elastic waves in the elastic punch and plug, schematically shown in space coordinate-time diagrams, suggest that the elastic wave in the plug is the probable cause of the inconsistency between the theoretical and experimental data of the previous investigation. In fact, the diagrams indicate that the shock wave transmitted in the medium across the medium-plug interface exerts an effect on the compaction process when the plug length does not exceed what is termed the first critical length. In cases when the effect of die wall friction is neglected, the mean green density-initial powder length relation of the copper medium is obtained from a theoretical approximation based on energy of the medium for the compaction with the sum of the initial powder length and the plug length being constant. This relation indicates that the effect of elasticity of the plug is large as the plug length becomes large. The second critical plug length at which the effect of elasticity becomes balanced with the effect of die wall friction is established by this relation and by the previously computed density-length relation with the effect of die wall friction taken into account. More specifically, these two relations provide a relation involving the first and second critical-plug lengths. The relation inferred as such agrees qualitatively with the previous experimental data in the examined region of the initial powder length. This qualitative agreement suggests that if the effects of elasticity and die wall friction are considered, a satisfactory theoretical and experimental agreement could be obtained. Therefore, the mean green density-initial powder length relation is computed taking into account both the effects. The computed relation agrees quantitatively with the previous experimental data even for short initial powder lengths and long plug lengths.

A Finite Element Cavitation Algorithm: Application/Validation

A mass-conserving simulation algorithm for cavitating hydrodynamic lubrication has been described elsewhere. The algorithm, which is particularly well adapted to finite element implementation, is outlined qualitatively and demonstrated quantitatively through bearing applications studied experimentally by others. Present simulation results and previous experimental data agree relatively closely for these applications, providing limited validations of the algorithm and suggesting new lines of investigation.

Pressure Effects of Neon and Argon on the 535 nm Thallium Line

Experimental studies of collisional broadening and shift of the 535 nm thallium line perturbed by neon and argon were performed using a pressure-scanned Fabry-Perot interferometer. The 535 nm line was excited by irradiation of the thallium vapour with the resonance thallium line (377.68 nm). The present results are compared with previous experimental data obtained by different methods as well as with theoretical ones.