Bond disproportionation and dynamical charge fluctuations in the perovskite rare earth nickelates

We present a theory describing the local electronic properties of the perovskite rare earth nickelates--materials which have negative charge transfer energies, strong O $2p$ -- Ni $3d$ covalence, and breathing mode lattice distortions at the origin of highly studied metal-insulator and antiferromagnetic ordering transitions. Utilizing a full orbital, full correlation double cluster approach, we find strong charge fluctuations in agreement with a bond disproportionation interpretation. The unique double cluster formulation permits the inclusion of necessary orbital degeneracies and Coulomb interactions to calculate resonant x-ray spectral responses, with which we find excellent agreement with well-established experimental results. This previously absent, crucial link between theory and experiment provides validation of the recently proposed bond disproportionation theory, and provides an analysis methodology for spectroscopic studies of engineered phases of nickelates and other high valence transition metal compounds

Art, Science, or Trade

Several definitions of the term engineer are presented, discussed, and contrasted with the term scientist . These definitions demonstrate the fundamental differences between engineers and scientists and their professions The engineering method is compared with the scientific method and the value of each is discussed. Several aspects of engineering education are covered. The need for more liberally educated engineers is emphasized and the impact of computers on engineering education and the engineering profession is discussed. The value of a good science foundation in an undergraduate engineering program is also stressed. An engineering education is only as good as the engineering educators and for this reason it is imperative that the best engineers be involved in education. This is especially true in engineering design courses. Practicing engineers with practical experience must be brought into the education arena to share their experiences. Engineering and science are different professions. Each has a different set of goals and different methods of achieving these goals. This division or separation of science and engineering serves the best interest of each profession and also mankind as a whole

The Troubled Rule of Nondiscrimination in Taxing Foreign Direct Investment

[Abstract needed

Antilegalistic Approaches to Resolving Disputes Between Governments: A Comparison of the International Tax and Trade Regimes

International agreements and institutions cannot bind governments. They can facilitate cooperation, however, by changing the domestic political context in which governments make decisions based on self-interest. The Article uses this insight to analyze the polar cases of dispute settlement in the General Agreement on Tariffs and Trade (GA7T) and in income tax treaties. Although these agreements share common goals and principles, they employ radically different dispute settlement mechanisms. The GATT employs a legalistic, quasi-judicial system; tax treaties rely on intergovernmental consultation and negotiation. The Article argues that legalistic dispute settlement performs an important role in the international trade regime by managing retaliatory strategies and by generating and disseminating information about the capabilities and intentions of the parties to the regime. The Article further argues that, in the international tax regime, legalistic procedures are less necessary for these purposes. Any incremental benefits of employing such procedures would likely be outweighed by the costs. These costs include the possibility that confrontational and adversarial processes will undermine ongoing relationships; that political forces will lead to conspicuous cases of noncompliance that will threaten the prestige of the regime; that the decisions of politically unaccountable international dispute settlement bodies will be perceived as lacking in legitimacy; and that legalistic systems will fail to be sufficiently flexible to accommodate treaty rules to changing circumstances and issues. The Article concludes that it would be misguided to redesign tax treaty dispute settlement to resemble the GATT model or to bring income tax disputes under the jurisdiction of international trade or investment agreements with legalistic dispute settlement systems

Justice Blackmun\u27s Federal Tax Jurisprudence

During his tenure on the Supreme Court, Justice Blackmun was widely regarded as the Court\u27s authority on tax matters. Justice Blackmun viewed tax law not merely as a technical specialty, but as a microcosm of the legal system. His numerous tax opinions involve a wide range of issues of constitutional law, criminal law, administrative procedure, court procedure, and statutory interpretation. This Article begins by discussing two of Justice Blackmun\u27s tax opinions involving constitutional issues. Justice Blackmun refused to create special constitutional rules for tax cases. Instead, he applied generally applicable principles, but with great sensitivity to how those principles would work in the tax context. The Article next examines Justice Blackmun\u27s opinions in several tax cases involving statutory interpretation. Justice Blackmun\u27s approach can best be described as relying on practical reasoning. He analyzed these cases in light of the underlying structure and logic of the income tax system, and his analyses are remarkably consistent with the economic concept of income elaborated by tax scholars. But Justice Blackmun also carefully evaluated and balanced a range of other - and often conflicting - factors, including the precise statutory language, context, legislative history, statutory purposes in addition to reflecting economic income, post-enactment developments, and the practical consequences of adopting alternative interpretations. His opinions typically weave together multiple strands of argument in a way that deals fairly with both sides of the issue. The Article argues that the Court is institutionally capable of carrying out this kind of analysis, and that this approach is essential if the Court is to fulfill its proper role in the administration of the tax system

RSM 1.0 user's guide: A resupply scheduler using integer optimization

The Resupply Scheduling Model (RSM) is a PC based, fully menu-driven computer program. It uses integer programming techniques to determine an optimum schedule to replace components on or before a fixed replacement period, subject to user defined constraints such as transportation mass and volume limits or available repair crew time. Principal input for RSJ includes properties such as mass and volume and an assembly sequence. Resource constraints are entered for each period corresponding to the component properties. Though written to analyze the electrical power system on the Space Station Freedom, RSM is quite general and can be used to model the resupply of almost any system subject to user defined resource constraints. Presented here is a step by step procedure for preparing the input, performing the analysis, and interpreting the results. Instructions for installing the program and information on the algorithms are given

An Experimental Investigation of Torque Loss in a Die Cast Aluminum Threaded Fastener Joint

The intent of this study was to investigate experimentally the root cause of torque loss in a die-cast aluminum threaded fastener joint that is used to assemble an engine mount to the front cover of an automotive engine. The primary goal was to develop a practical experimental method to characterize threaded fastener joints in situ. Using installation torque measurements, hardness test results, and a DC nut runner, joint attributes were measured, and the data was evaluated. This investigation demonstrated that the incompatibility of the mechanical properties at the interface of the housing and fastener resulted in significant torque loss. Further investigations are planned to study cost effective design modifications

Automorphic properties of low energy string amplitudes in various dimensions

This paper explores the moduli-dependent coefficients of higher derivative interactions that appear in the low-energy expansion of the four-graviton amplitude of maximally supersymmetric string theory compactified on a d-torus. These automorphic functions are determined for terms up to order D^6R^4 and various values of d by imposing a variety of consistency conditions. They satisfy Laplace eigenvalue equations with or without source terms, whose solutions are given in terms of Eisenstein series, or more general automorphic functions, for certain parabolic subgroups of the relevant U-duality groups. The ultraviolet divergences of the corresponding supergravity field theory limits are encoded in various logarithms, although the string theory expressions are finite. This analysis includes intriguing representations of SL(d) and SO(d,d) Eisenstein series in terms of toroidally compactified one and two-loop string and supergravity amplitudes.Comment: 80 pages. 1 figure. v2:Typos corrected, footnotes amended and small clarifications. v3: minor corrections. Version to appear in Phys Rev