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 & Population. The organization has 19024 authors who have published 39922 publications receiving 1414699 citations. The organization is also known as: RPI & Rensselaer Institute.

A simple model for sector zoning in slowly grown crystals; implications for growth rate and lattice diffusion, with emphasis on accessory minerals in crustal rocks

Abstract: Abstract The occurrence of sector zoning in minerals of regional metamorphic or low-temperature intrusive origin implies that rapid growth is not required for the development of this particular form of homogeneous disequilibrium. It is shown here that sector zoning can be a natural consequence simply of slow lattice diffusion. Given anisotropic surface enrichment coupled with the low dilfusivities typical of highly charged elements in refractory accessory minerals such as zircon and titanite, sector zoning can arise even in cases of growth rjates as low as a few micrometers per million years. According to the proposed model, the development of sector zoning depends upon the competition between growth rate (V) and lattice diffusion (Di) within the near-surface layer (l), such that above a critical value of Vl/Di (~0.5-3), sector zoning is unavoidable in crystals that exhibit selective enrichment on some growth surfaces. Known diffusivities of rare earth elements in zircon and titanite lead to the expectation of sector zoning in these minerals with respect to REEs for reasonable geologic growth rates. Even in the case of clinopyroxene, diffusion of REEs and high field-strength elements may be slow enough to contribute to the development of sector zoning in laboratory-grown crystals.

Information systems as a reference discipline for new product development

Abstract: Baskerville and Myers (2002) recently suggested that the information systems (IS) field has "come of age" and that it can now serve as a reference discipline for other fields. In this article, the discourse about their vision is extended by considering the potential for the IS field to contribute to new product development (NPD) research. It is argued that the rapid infusion of information technology (IT) along four dimensions of product development process management, project management, information and knowledge management, and collaboration and communication raises several important NPD research issues. These issues could be addressed by drawing from extant theories and models in the IS field. By employing NPD as the context, other issues that underlie the new role envisioned for the IS field are also identified.

Fault-Tolerant Interior-Permanent-Magnet Machines for Hybrid Electric Vehicle Applications

Abstract: Multiphase interior permanent magnet (IPM) motors are very good candidates for hybrid electric vehicle applications. High torque pulsation is the major disadvantage of most IPM motor configurations. A five-phase IPM motor with low torque pulsation is discussed. The mathematical model of the five-phase motor is given. A control strategy that provides fault tolerance to five-phase permanent-magnet motors is introduced. In this scheme, the five-phase system continues operating safely under loss of up to two phases without any additional hardware connections. This feature is very important in traction and propulsion applications where high reliability is of major importance. The system that is introduced in this paper will guarantee high efficiency, high performance, and high reliability, which are required for automotive applications A prototype four-pole IPM motor with 15 stator slots has been built and is used for experimental verification.

The Evolution of Truly Social Cognition: The Core Configurations Model

Abstract: This article introduces a vocabulary suitable for evolutionary analyses in the human cognitive, social, and behavioral sciences. The vocabulary carves a middle way between advocates and critics of evolutionary perspectives by substituting the concept of repeated assembly for nature-nurture dualism. A model of core configurations-based on human morphology and ecology in human evolutionary history-is presented, and I argue that these configurations of face-to-face groups are the selective context for uniquely human mental systems. Hence, human cognition is "truly social,"" specialized for group living. The relevance of the core configuration model is illustrated with respect to two areas of interest to social psychologists: the self and social identity, and distributed cognition and shared reality. A final section illustrates the integrative power of the core configuration model with a brief comparison of the social and cognitive tasks faced by scientists and foragers.