A computer program for calculating design and off-design performance for turbojet and turbofan engines

Program uses component performance maps to enable user to do analytical engine cycle calculations. Through scaling procedure, each of the component maps can be used to represent a family of maps. Either convergent or convergent-divergent nozzles may be used

Quantum computation with Turaev-Viro codes

The Turaev-Viro invariant for a closed 3-manifold is defined as the contraction of a certain tensor network. The tensors correspond to tetrahedra in a triangulation of the manifold, with values determined by a fixed spherical category. For a manifold with boundary, the tensor network has free indices that can be associated to qudits, and its contraction gives the coefficients of a quantum error-correcting code. The code has local stabilizers determined by Levin and Wen. For example, applied to the genus-one handlebody using the Z_2 category, this construction yields the well-known toric code. For other categories, such as the Fibonacci category, the construction realizes a non-abelian anyon model over a discrete lattice. By studying braid group representations acting on equivalence classes of colored ribbon graphs embedded in a punctured sphere, we identify the anyons, and give a simple recipe for mapping fusion basis states of the doubled category to ribbon graphs. We explain how suitable initial states can be prepared efficiently, how to implement braids, by successively changing the triangulation using a fixed five-qudit local unitary gate, and how to measure the topological charge. Combined with known universality results for anyonic systems, this provides a large family of schemes for quantum computation based on local deformations of stabilizer codes. These schemes may serve as a starting point for developing fault-tolerance schemes using continuous stabilizer measurements and active error-correction.Comment: 53 pages, LaTeX + 199 eps figure

The dynamic impact of fundamental tax reform part 2 : extensions

In this second of two articles on the economic impact of fundamental tax reform, Gregory Huffman and Evan Koenig extend their earlier framework for analyzing how the adoption of a flat-rate consumption tax would affect the economy over time. They argue that if tax reform is to be successful in stimulating investment and raising long-run living standards, then it is important that ways be found to avoid increasing the rate of labor-income taxation. Increases in labor-income tax rates can undo the positive economic effects of a cut in the rate of capital-income taxation. Conversely, cuts in labor-income tax rates reinforce savings incentives and contribute to higher steady-state levels of consumption. Huffman and Koenig also demonstrate that the economy’s immediate response to tax reform is muted—and the overall adjustment process can be substantially prolonged—when firms find it expensive to add quickly to their stocks of plant and equipment.Taxation ; Tax auditing ; Tax reform

Preliminary QCGAT program test results

NASA Lewis Research Center is conducting a program to demonstrate that large commercial engine technology can be applied to general aviation engines to reduce noise, emissions and fuel consumption and to develop new technology where required. The overall engine program, design, and technology incorporated into the QCGAT engines are described. In addition, preliminary engine test results are presented and compared to the technical requirements the engines were designed to meet

Feasibility of modifying the high resolution infrared radiation sounder (HIRS/2) for measuring spectral components of Earth radiation budget

The concept of adding four spectral channels to the 20 channel HIRS/2 instrument for the purpose of determining the origin and profile of radiant existence from the Earth's atmosphere is considered. Methods of addition of three channels at 0.5, 1.0 and 1.6 micron m to the present 0.7 micron m visible channel and an 18-25 micron m channel to the present 19 channels spaced from 3.7 micron m to 15 micron m are addressed. Optical components and physical positions were found that permit inclusion of these added channels with negligible effect on the performance of the present 20 channels. Data format changes permit inclusion of the ERB data in the 288 bits allocated to HIRS for each scan element. A lamp and collimating optic assembly may replace one of the on board radiometric black bodies to provide a reference source for the albedo channels. Some increase in instrument dimensions, weight and power will be required to accommodate the modifications

Fabrication and test of digital output interface devices for gas turbine electronic controls

A program was conducted to develop an innovative digital output interface device, a digital effector with optical feedback of the fuel metering valve position, for future electronic controls for gas turbine engines. A digital effector (on-off solenoids driven directly by on-off signals from a digital electronic controller) with optical position feedback was fabricated, coupled with the fuel metering valve, and tested under simulated engine operating conditions. The testing indicated that a digital effector with optical position feedback is a suitable candidate, with proper development for future digital electronic gas turbine controls. The testing also identified several problem areas which would have to be overcome in a final production configuration

The dynamic impact of fundamental tax reform part 1: the basic model

The Internal Revenue Service remains unpopular, the U.S. savings rate remains low, and pressure to efficiently raise significant new tax revenues seems certain to grow once the baby boom generation reaches retirement age. Consequently, it is likely that alternatives to the current income tax system will receive substantial political and media attention in coming years. In this first of two articles on the economic impact of fundamental tax reform, Evan Koenig and Gregory Huffman describe a framework for analyzing how the adoption of a flat-rate consumption tax would affect the economy over time. Their analysis indicates that replacing the income tax with a consumption tax would have an immediate positive impact on saving and lead, in the long run, to higher levels of consumption, wages, and stock prices and to lower interest rates. In the short run, however, interest rates would probably rise, and consumption and stock prices would probably decline.Taxation

Analysis and design of digital output interface devices for gas turbine electronic controls

A trade study was performed on twenty-one digital output interface schemes for gas turbine electronic controls to select the most promising scheme based on criteria of reliability, performance, cost, and sampling requirements. The most promising scheme, a digital effector with optical feedback of the fuel metering valve position, was designed

Comparative assessment of out-of-core nuclear thermionic power systems

The hardware selections available for fabrication of a nuclear electric propulsion stage for planetary exploration were explored. The investigation was centered around a heat-pipe-cooled, fast-spectrum nuclear reactor for an out-of-core power conversion system with sufficient detail for comparison with the in-core system studies completed previously. A survey of competing power conversion systems still indicated that the modular reliability of thermionic converters makes them the desirable choice to provide the 240-kWe end-of-life power for at least 20,000 full power hours. The electrical energy will be used to operate a number of mercury ion bombardment thrusters with a specific impulse in the range of about 4,000-5,000 seconds