This unexpected behavior leads to an investigation of dispersion statistically and with a numerical simulator. Test runs using reservoir simulators show that the echo dispersivity is indeed unaffected by flow-direction changes and is constant for a homogeneous and noncommunicating layered permeable medium. The simulated echo dispersivity on permeability fields generated, however, grows with length when there is permeability variation. Polyurethanes are used extensively in industrial and consumer products, because the chemistry involved allows for significant diversity in physical and chemical properties. Polyurethanes are not typically employed in tissue engineering, as their degradation products are toxic.
Osteoblasts can grow on such foams.
Adding aqueous protein solutions results in the solutes incorporating covalently into the material. We have created a series of catalysts that promote the creation of ether-carbonate copolymers. When these polyols are used in polyurethanes, the carbonate repeats provide additional points where hydrolytic degradation can occur. In line with the semiconductor roadmap, continuous improvement of tools and processing methods is necessary for future generations of microchips. In parallel with the development of better processing hardware, process integration will be a key issue in the coming decade.