Age-hardening characteristics in a dental low-gold alloy composed of 40.0 wt% Au-35.0 wt% Ag-7.9 wt% Pd-7.0 wt% Cu-5.0 wt% In-3.5 wt% Zn-1.5 wt% Sn, were investigated by means of the hardness test, XRD study, SEM observations and EPMA. The following results were obtained. The age-hardening was characterized by a precipitation of Cu-rich alpha2 phase in the a phase. The softening that occurred f...

Title of dissertation: Dynamics of Erythrocytes and Microcapsules Walter R. Dodson III Doctor of Philosophy, 2008 Fischell Department of Bioengineering Dissertation directed by: Panagiotis Dimitrakopoulos, Ph.D. Department of Chemical and Biomolecular Engineering The erythrocytes are the primary carriers of oxygen and carbon dioxide to and from the systemic tissue. The ability of these cells to...

Using molecular dynamics simulations of a generic model, we observe strain hardening in highly cross-linked polymer glasses under tensile deformation. We show that formation of microvoids, without bond breaking, constitutes the microscopic origins of strain hardening. A well-defined functional form is observed for the void size distribution that is consistent with voids in dense equilibrium Len...

Strain-controlled fatigue of Mg–1Mn-0.5Nd (wt.%) alloy were studied by experiment and simulation. The microstructure was made up a dispersion strongly texture grains (13%) embedded in matrix with random texture. cyclic stress-strain curves showed limited tension-compression anisotropy because the Cyclic hardening under compression softening tension occurred due to presence twinning. Moreover, t...

Dependence of mechanical properties of geomaterials on the variable chemical environment or advancement of chemical or mineralogical reactions is known to be a crucial factor in many cases of mechanical stability of geo-masses. Processes of mineral dissolution usually results in material weakening while precipitation of minerals such as of silica in aging or calcite in clay fractures may lead t...

Structural stability of a multiferroic compound CuFeO2 belonging to the delafossite family has been investigated at high pressures using in-situ Raman spectroscopy. At ambient conditions, CuFeO2 has a rhombohedral structure with space group R3m. It has two Raman active modes, identified as Eg and A1g. Both Raman mode frequencies harden with pressure. At 18 GPa, the doubly degenerate mode Eg spl...

Nonlinear oscillators with hardening and softening cubic Duffing nonlinearity are considered. Such classical conservative oscillators are known to have an amplitude-dependent period. In this work, we design oscillators with the Duffing-type restoring force but an amplitude-independent period. We present their Lagrangians, equations of motion, conservation laws, as well as solutions for motion.

The influence of thermomechanical deformation on the residual stresses caused by quenching in bar shaped specimens of heat treatable steel 42CrMo4 has been investigated using a mechanical method for detemining the distribution of residual stresses of the first kind. The results obtained show that the residual stress distribution after quenching is dected by the strengthening and softening of th...

The mechanics of the cutting process on the microscopic level differ fundamentally from the conventional macro cutting. For example, the tool edge radius influences the cutting mechanism in micro machining significantly with regard to the effective rake angle, the minimum chip thickness, the dominance of ploughing, and the related elasto-plastic deformation of the workpiece material. These phen...

This work presents the nonlinear analysis of dynamics large strain deformation subsea flowlines and jumpers conveying two-phase fluid. Precisely, flexible pipes operating in stated condition undergo deformations. Thus, known deterministic model system is solved using method discretized perturbation. this study obtained natural frequency simply supported modelled theory. Results show that both h...