Rensselaer Polytechnic Institute

About: Rensselaer Polytechnic Institute is a education organization based out in Troy, New York, United States. It is known for research contribution in the topics: Terahertz radiation & Finite element method. The organization has 19024 authors who have published 39922 publications receiving 1414699 citations. The organization is also known as: RPI & Rensselaer Institute.

Regulatory focus and new venture performance: A study of entrepreneurial opportunity exploitation under conditions of risk versus uncertainty

Abstract: Research on cognitive fit suggests that entrepreneurs will be most successful at leading their firms when approaching the entrepreneurial process through the self-regulatory mode that most closely matches the requirements of their environment and its accompanying perspective on the nature of entrepreneurial opportunities. Consistent with the discovery view of entrepreneurial opportunities, it is suggested that a prevention focus will be the most effective self-regulatory mode for entrepreneurs leading their firms within stable industry environments, which are characterized by risk. Building from the creation view of entrepreneurial opportunities, it is argued that a promotion focus will be the most effective self-regulatory mode for entrepreneurs leading their firms within dynamic industry environments, which are characterized by uncertainty. These arguments are tested using a national (United States) random sample of 201 lead entrepreneurs. The findings indicate that in dynamic environments, entrepreneurs' promotion focus is positively associated with venture performance (i.e., lagged measures of revenue and employment growth), while entrepreneurs' prevention focus is negatively related to performance in such environments. In both cases, these effects are found to be fully mediated by deviation from firms' original business concepts. In stable environments, however, no significant relationships between entrepreneurs' promotion or prevention focus and new venture performance were observed. These results suggest that low cognitive fit (a mismatch between entrepreneurs' mode of self-regulation and the decision-making context in which they operate) is more damaging in dynamic environments (i.e., a context of uncertainty) than in stable environments (i.e., a context of risk). Copyright © 2009 Strategic Management Society.

Mechanical Behavior of Alumina/Poly(methyl methacrylate) Nanocomposites

Abstract: Alumina/poly(methyl methacrylate) (PMMA) nanocomposites were synthesized using 38 and 17 nm alumina nanoparticles. At an optimum weight fraction, the resulting nanocomposites display a room-temperature brittle-to-ductile transition in uniaxial tension with an increase in the strain-to-failure that averages 40% strain and the appearance of a well-defined yield point in uniaxial tension. Concurrently, the glass transition temperature (Tg) of the nanocomposites drops by more than 20 °C. The brittle-to-ductile transition is found to depend on poor interfacial adhesion between polymer and nanoparticle. This allows the nucleation of voids, typically by larger particles (∼100 nm), which subsequently expand during loading. This void formation suppresses craze formation and promotes delocalized shear yielding. In addition, the reduction in Tg shrinks the shear yield envelope, further promoting this type of yield behavior. The brittle-to-ductile phenomenon is found to require both larger particles for void growth a...

Preisach modeling of piezoceramic and shape memory alloy hysteresis

Abstract: Smart materials such as piezoceramics, magnetostrictive materials, and shape memory alloys exhibit hysteresis, and the larger the input signal the larger the effect. Hysteresis can lead to unwanted harmonics, inaccuracy in open loop control, and instability in closed loop control. The Preisach independent domain hysteresis model has been shown to capture the major features of hysteresis arising in ferromagnetic materials. Noting the similarity between the microscopic domain kinematics that generate static hysteresis effects in ferromagnetics, piezoceramics, and shape memory alloys (SMAs), we apply the Preisach model for the hysteresis in piezoceramic and shape memory alloy materials. This paper reviews the basic properties of the Preisach model, discusses control-theoretic issues such as identification, simulation, and inversion, and presents experimental results for piezoceramic sheet actuators bonded to a flexible aluminum beam, and a Nitinol SMA wire muscle that applies a bending force to the end of a beam.

New materials graphyne, graphdiyne, graphone, and graphane: review of properties, synthesis, and application in nanotechnology

Abstract: Plenty of new two-dimensional materials including graphyne, graphdiyne, graphone, and graphane have been proposed and unveiled after the discovery of the "wonder material" graphene. Graphyne and graphdiyne are two-dimensional carbon allotropes of graphene with honeycomb structures. Graphone and graphane are hydrogenated derivatives of graphene. The advanced and unique properties of these new materials make them highly promising for applications in next generation nanoelectronics. Here, we briefly review their properties, including structural, mechanical, physical, and chemical properties, as well as their synthesis and applications in nanotechnology. Graphyne is better than graphene in directional electronic properties and charge carriers. With a band gap and magnetism, graphone and graphane show important applications in nanoelectronics and spintronics. Because these materials are close to graphene and will play important roles in carbon-based electronic devices, they deserve further, careful, and thorough studies for nanotechnology applications.