Transient Analysis of a Magnetic Heat Pump

An experimental heat pump that uses a rare earth element as the refrigerant is modeled using NASTRAN. The refrigerant is a ferromagnetic metal whose temperature rises when a magnetic field is applied and falls when the magnetic field is removed. The heat pump is used as a refrigerator to remove heat from a reservoir and discharge it through a heat exchanger. In the NASTRAN model the components modeled are represented by one-dimensional ROD elements. Heat flow in the solids and fluid are analyzed. The problem is mildly nonlinear since the heat capacity of the refrigerant is temperature-dependent. One simulation run consists of a series of transient analyses, each representing one stroke of the heat pump. An auxiliary program was written that uses the results of one NASTRAN analysis to generate data for the next NASTRAN analysis

Administrative Process Reform in a Discretionary Age: The Role of Social Consequences

The basic rulemaking procedures of the Administrative Procedure Act have remained intact for thirty-eight years, but now Congress is seriously considering reform of those generic rules. To evaluate the merits of these reform proposals, we must develop criteria against which to judge them. Although procedural reforms are commonly judged against the goals of fairness, accuracy, and procedural efficiency, Professors Schroeder and Magat argue that these are insufficient criteria to apply to administrative process reforms at a time when agencies possess substantial discretion in the rulemaking process. In such a context, procedures have an impact on society in ways not adequately evaluated by the traditional criteria. Discretion means that agencies may choose from a set of possible rules, none of which has been foreclosed by the enabling legislation of the agency. Procedures influence which choices the agency makes and, because these choices alter the regulations and restrictions under which society operates, they affect the social consequences of regulation. This article describes a model of participant behavior necessary to trace the effects of procedures on the social consequences of regulation, articulates a set of criteria to evaluate these social consequences, and then analyzes two frequently proposed generic reforms to the APA: mandatory regulatory impact analysis and oversight by the Office of Management and Budget

The ℓ2\ell^2-homology of even Coxeter groups

Given a Coxeter system (W,S), there is an associated CW-complex, Sigma, on which W acts properly and cocompactly. We prove that when the nerve L of (W,S) is a flag triangulation of the 3-sphere, then the reduced $\ell^2$-homology of Sigma vanishes in all but the middle dimension.Comment: 15 pages, 1 figur