24,689 research outputs found
Evaluation of the gust-alleviation characteristics and handling qualities of a free-wing aircraft
Dynamic characteristics of aircraft with wings free to pivot spanwise axi
Survey of fracture toughness test methods
Comprehensive survey presents current methods of fracture toughness testing that are based on linear elastic fracture mechanics. General principles of the basic two dimensional crack stress field model are discussed in relation to real three dimensional specimens. Methods of test instrumentation and procedure are described
Quasilocal Energy for a Kerr black hole
The quasilocal energy associated with a constant stationary time slice of the
Kerr spacetime is presented. The calculations are based on a recent proposal
\cite{by} in which quasilocal energy is derived from the Hamiltonian of
spatially bounded gravitational systems. Three different classes of boundary
surfaces for the Kerr slice are considered (constant radius surfaces, round
spheres, and the ergosurface). Their embeddings in both the Kerr slice and flat
three-dimensional space (required as a normalization of the energy) are
analyzed. The energy contained within each surface is explicitly calculated in
the slow rotation regime and its properties discussed in detail. The energy is
a positive, monotonically decreasing function of the boundary surface radius.
It approaches the Arnowitt-Deser-Misner (ADM) mass at spatial infinity and
reduces to (twice) the irreducible mass at the horizon of the Kerr black hole.
The expressions possess the correct static limit and include negative
contributions due to gravitational binding. The energy at the ergosurface is
compared with the energies at other surfaces. Finally, the difficulties
involved in an estimation of the energy in the fast rotation regime are
discussed.Comment: 22 pages, Revtex, Alberta-Thy-18-94. (the approximations in Section
IV have been improved. To appear in Phys. Rev. D
Similitude requirements and scaling relationships as applied to model testing
The similitude requirements for the most general test conditions are presented. These similitude requirements are considered in relation to the scaling relationships, test technique, test conditions (including supersonic flow), and test objectives. Particular emphasis is placed on satisfying the various similitude requirements for incompressible and compressible flow conditions. For free flying models tests, the test velocities for incompressible flow are scaled from Froude number similitude requirements and those for compressible flow are scaled from Mach number similitude requirements. The limitations of various test techniques are indicated, with emphasis on the free flying model
Development of Replacement Heifers using Combinations of Three Forage Types and Feed Supplements (with or without Broiler Litter)
The proper management of replacement heifers is an essential component of successful cow/calf operations. The level of management and nutrition applied to replacement heifers as calves and yearlings can impact their subsequent reproductive performance and productivity
Church and State - Taxation of Religious Organizations - Benefits Granted by Federal and State Governments
Analytical study of a free-wing/free-trimmer concept
The free-wing/free-trimmer is a NASA-Conceived extension of the free-wing concept intended to permit the use of high-lift flaps. Wing pitching moments are balanced by a smaller, external surface attached by a boom or equivalent structure. The external trimmer is, itself, a miniature free wing, and pitch control of the wing-trimmer assembly is effected through a trailing-edge control tab on the trimmer surface. The longitudinal behavior of representative small free-wing/free-trimmer aircraft was analyzed. Aft-mounted trimmer surfaces are found to be superior to forward trimmers, although the permissible trimmer moment arm is limited, in both cases, by adverse dynamic effects. Aft-trimmer configurations provide excellent gust alleviation and meet fundamental stick-fixed stability criteria while exceeding the lift capabilities of pure free-wing configurations
Analysis of the linearity characteristics, tape recorders and compensation effects in the FM/FM telemetry system
Linearity characteristics, tape recorder effects, and tape speed compensation effects in FM/FM TELEMETRY syste
Molecular Beams
Contains reports on three research projects.Lincoln Laboratory (Purchase Order DDL B-00283)United States ArmyUnited States NavyUnited States Air Force (Contract AF19(604)-5200
Atomic Beams
Contains research objectives and reports on two research projects.Lincoln Laboratory, Purchase Order DDL-B222Department of the ArmyDeparment of the NavyDepartment of the Air Force under Contract AF19(122)-45
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