Linear, friction-induced vibration and aeroelastic flutter problems are governed by second-order differential equations of motion in which the stiffness matrix and often damping matrix are asymmetric. Asymmetric systems are prone to unstable vibration (flutter) as a parameter reaches a critical value, when the real part of a pair of complex poles crosses the vertical imaginary axis of the s-pla...

Adipose-derived stromal cells (ADSCs) are attractive autologous cell sources for cartilage repair given their relative abundance and ease of isolation. Previous studies have demonstrated the potential of extracellular matrix (ECM) molecules as three-dimensional (3D) scaffolds for promoting chondrogenesis. However, few studies have compared the effects of varying types or doses of ECM molecules ...

The stiffness of the extracellular matrix can profoundly influence cell and tissue behaviors. Thus there is an emerging emphasis on understanding how matrix mechanical environments are established, regulated, and modified. Here we develop a microrheometric assay to measure the mechanical properties of a model extracellular matrix (type I collagen gel) and use it to explore cytokine-induced, cel...

The stiffness of the extracellular matrix can profoundly influence cell and tissue behaviors. Thus there is an emerging emphasis on understanding how matrix mechanical environments are established, regulated, and modified. Here we develop a microrheometric assay to measure the mechanical properties of a model extracellular matrix (type I collagen gel) and use it to explore cytokine-induced, cel...

This paper discusses static stability of a planar object grasped by multifingers with three joints. Each individual joint (prismatic joint or revolute joint) is modeled as a linear spring stiffness. The object mass and the link masses are also included. We consider not only pure rolling contact but also frictionless sliding contact. The grasp stability is investigated using the potential energy...

Static stiffness is an important indicator of the performance of a rolling guide, having direct influence on the stiffness and precision of computer numerically controlled (CNC) machine tools. After preloading the rolling guide, an outward elastic deformation is generated at the carriage skirt, which leads to a decrease in the static stiffness of the rolling guide. Therefore, there would be rel...

BACKGROUND In ventricular dilatation or hypertrophy, an elevated end-diastolic pressure is often assumed to be secondary to increased myocardial stiffness, but stiffness is rarely measured in vivo because of difficulty. We measured in vitro passive stiffness of volume- or pressure-overloaded myocardium mainly from congenital heart disease. METHODS AND RESULTS Endocardial ventricular biopsies ...

neither damage mechanics model nor elastoplastic constitutive law can solely describe the behavior of concrete satisfactorily. in fact, they both fail to represent proper unloading slopes during cyclic loading. to overcome the disadvantages of pure plastic models and pure damage approaches, the combined effects need to be considered. in this regard, various classes of plastic-damage models have...

Combined approximations (CA) is an efŽ cient method for reanalysis of structures where binomial series terms are used as basis vectors in reduced basis approximations. In previous studies high-quality approximations have been achieved for large changes in the design, but the reasons for the high accuracy were not fully understood. In this work some typical cases, where exact and accurate soluti...