626 Matching Results

Search Results

Advanced search parameters have been applied.

Approximate effect of leading-edge thickness, incidence angle, and inlet mach number on inlet losses for high-solidity cascades of low cambered blades

Description: Report presenting an approximate, theoretical analysis of the inlet or induction losses due to subsonic flow into a high-solidity cascade of finite thickness blades at incidence angle. Results indicated that the losses can become considerable for large deviations from the design incidence such as compressor off-design operating conditions. Results regarding the computational results, significance of assumptions and limitations, comparison of theoretical approximation with actual compressor results, and applicability of the results are provided.
Date: December 1954
Creator: Wright, Linwood C.
Partner: UNT Libraries Government Documents Department

An experimental investigation at subsonic speeds of a scoop-type air-induction system for a supersonic airplane

Description: Report presenting an investigation at subsonic speeds of a scoop-type air-induction system designed for use at subsonic and supersonic speeds. Measurements of the ram-recovery ratio and static pressures in a scoop-type intake on the upper surface of the fuselage were taken for a large range of mass-flow ratios, angles of attack, and angles of sideslip.
Date: July 19, 1951
Creator: Holzhauser, Curt A.
Partner: UNT Libraries Government Documents Department

An analytical study of the comparative performance of six air-induction systems for turbojet-powered airplanes designed to operate at Mach numbers up to 2.0

Description: Report presenting an extension of NACA RM A52C14 about inlet design and performance for Mach numbers of 1.5 to 2.0. A two-dimensional inviscid analysis is used to compare the performance of several types of inlets when used in conjunction with a turbojet engine with constant-volume air flow. Results regarding air delivery and air requirements, drag factors, evaluation of inlet performance, significance of the drag summation, and inlet and engine-matching considerations are provided.
Date: October 9, 1953
Creator: Watson, Earl C.
Partner: UNT Libraries Government Documents Department

Summary report on the induction of water to the inlet air as a means of internal cooling in aircraft-engine cylinders

Description: Report presenting investigations of a full-scale air-cooled aircraft-engine cylinder of 202-cubic-inch displacement to determine the effects of internal cooling by water induction on the maximum permissible power and output of an internal-combustion engine. Results regarding the maximum permissible engine performance, engine temperatures, and constant inlet-air pressure investigations are provided.
Date: August 15, 1942
Creator: Rothrock, Addison M. & Jones, Anthony W.
Partner: UNT Libraries Government Documents Department

Dependence of Magnetic Hysteresis upon Wave Form

Description: Report issued by the Bureau of Standards over studies on magnetic hysteresis and its dependence upon wave form. Methods and equipment used during the studies are presented and discussed. This report includes tables, and illustrations.
Date: 1909
Creator: Lloyd, Morton G.
Partner: UNT Libraries Government Documents Department

An investigation at transonic speeds of the aerodynamic characteristics of an air inlet installed in the root of a 45 degree sweptback wing

Description: Report presenting an investigation in the transonic blowdown tunnel from Mach numbers 0.80 to 1.41 to determine the increments in lift and drag due to installation of a triangular-shaped air inlet in the root of a 45 degree sweptback wing and to determine the internal flow characteristics of the inlet. Results regarding pressure measurements of the inlet model, force measurements of basic and inlet models, and effect of boundary-layer bypass scoop and fuselage nose configuration on characteristics of inlet model are presented.
Date: October 1, 1952
Creator: Howell, Robert R. & Keith, Arvid L., Jr.
Partner: UNT Libraries Government Documents Department

The induction of water to the inlet air as a means of internal cooling in aircraft-engine cylinders

Description: Report presents the results of investigations conducted on a full-scale air-cooled aircraft-engine cylinder of 202-cubic inch displacement to determine the effects of internal cooling by water induction on the maximum permissible power and output of an internal-combustion engine. For a range of fuel-air and water-fuel ratios, the engine inlet pressure was increased until knock was detected aurally, the power was then decreased 7 percent holding the ratios constant. The data indicated that water was a very effective internal coolant, permitting large increases in engine power as limited by either knock or by cylinder temperatures.
Date: 1943
Creator: Rothrock, Addison M.; Krsek, Alois, Jr. & Jones, Anthony W.
Partner: UNT Libraries Government Documents Department

Induction furnace testing of the durability of prototype crucibles in a molten metal environment

Description: Engineered ceramic crucibles are commonly used to contain molten metal. Besides high temperature stability, other desired crucible characteristics include thermal shock resistance, minimal reaction with the molten metal and resistance to attack from the base metal oxide formed during melting. When used in an induction furnace, they can be employed as a “semi-permanent” crucible incorporating a dry ram backup and a ceramic cap. This report covers several 250-lb single melt crucible tests in an air melt induction furnace. These tests consisted of melting a charge of 17-4PH stainless steel, holding the charge molten for two hours before pouring off the heat and then subsequently sectioning the crucible to review the extent of erosion, penetration and other physical characteristics. Selected temperature readings were made throughout each melt. Chemistry samples were also taken from each heat periodically throughout the hold. The manganese level was observed to affect the rate of chromium loss in a non-linear fashion.
Date: September 1, 2005
Creator: Jablonski, Paul D.
Partner: UNT Libraries Government Documents Department

Cosmological AMR MHD with Enzo

Description: In this work, we present EnzoMHD, the extension of the cosmological code Enzoto include magnetic fields. We use the hyperbolic solver of Li et al. (2008) for the computation of interface fluxes. We use constrained transport methods of Balsara & Spicer (1999) and Gardiner & Stone (2005) to advance the induction equation, the reconstruction technique of Balsara (2001) to extend the Adaptive Mesh Refinement of Berger & Colella (1989) already used in Enzo, though formulated in a slightly different way for ease of implementation. This combination of methods preserves the divergence of the magnetic field to machine precision. We use operator splitting to include gravity and cosmological expansion. We then present a series of cosmological and non cosmologjcal tests problems to demonstrate the quality of solution resulting from this combination of solvers.
Date: January 1, 2009
Creator: Xu, Hao; Li, Hui & Li, Shengtai
Partner: UNT Libraries Government Documents Department

Longitudinal Resistive Stability of an Intense Charge Bunch in a Linear Accelerator

Description: A simple, but realistic, model is used to theoretically investigate the longitudinal stability of a non-relativistic bunch in the limit of small wall resistivity compared to self-reactance. It is shown that to lowest order--and in contrast with an infinitely long beam--that an intense bunch is stable against longitudinal collective modes. It is concluded that an induction linac remains a viable option as a driver for heavy ion inertial fusion.
Date: July 1, 1980
Creator: Channell, P.J.; Wurtele, J.S. & Sessler, A.M.
Partner: UNT Libraries Government Documents Department

The effect of entrance Mach number and lip shape on the subsonic characteristics of a scoop-type-air-induction system for a supersonic airplane

Description: Report presenting an investigation at subsonic speeds to determine the effects of lip shape and entrance Mach number on the characteristics of a scoop-type air-induction system designed for an airplane flying at supersonic speeds. Results regarding the ram-recovery ratio, static-pressure distribution, and drag are provided.
Date: January 9, 1952
Creator: Holzhauser, Curt A.
Partner: UNT Libraries Government Documents Department

Stacked insulator induction accelerator gaps

Description: Stacked insulators, with alternating layers of insulating material and conducting film, have been shown to support high surface electrical field stresses. We have investigated the application of the stacked insulator technology to the design of induction accelerator modules for the Relativistic-Klystron Two-Beam Accelerator program. The rf properties of the accelerating gaps using stacked insulators, particularly the impedance at frequencies above the beam pipe cutoff frequency, are investigated. Low impedance is critical for Relativistic-Klystron Two-Beam Accelerator applications where a high current, bunched beam is trsnsported through many accelerating gaps. An induction accelerator module designs using a stacked insulator is presented.
Date: May 1997
Creator: Houck, T. I.; Westenskow, G. A.; Kim, J. S.; Eylon, S.; Henestroza, E.; Yu, S. S. et al.
Partner: UNT Libraries Government Documents Department

Induction core performance

Description: Large masses of magnetic core material are required for many of the induction accelerator-based projects currently under study; the quantities required exceed 10<sup>7</sup> kg for a linear heavy-ion fusion driver, so core performance and cost are critical issues. We have evaluated cores of amorphous alloys from AlliedSignal and MRTI (Moscow Radio Technical Institute) and nanocrystalline alloys from Hitachi and Vacuumschmelze. The cores were of moderate size, between 1 and 11 kg. We characterized the materials in terms of the flux swing {Delta}B from -B<sub>remanent</sub> to +B<sub>saturation</sub>, and the energy loss versus dB/dt. We found sources for each material that could coat, wind, and then anneal the cores. This required the development of thin coatings that withstand 350-550° C anneal temperatures. The result is core performance near the ultimate small sample performance of each material, with higher {Delta}B and lower losses than the earlier approaches of using as-cast material or rewinding after anneal, in both, cases usually cowinding with thin mylar (-4µm thick). We are beginning system code studies of tradeoffs between {Delta}B and losses.
Date: August 14, 1998
Creator: Faltens, A; Meier, W R; Molvik, A W; Reginato, L & Smith, C
Partner: UNT Libraries Government Documents Department

Reaction field induced interatomic forces between atoms in the presense of a strong magnetic field

Description: It is shown that the reaction field induced in an atom by a strong magnetic field is of order B{alpha}² in atomic units (for magnetic field strength B and fine structure constant {alpha}). The reaction field causes a dipole-dipole interatomic potential energy to exist between a pair of atoms of order B<sup>3/2</sup>{alpha}<sup>7/2</sup>, such that B must be of order {alpha}<sup>-7/3</sup> for the interatomic energy to be of order one atomic unit. B of this order corresponds to a field strength of 1.66 x 10<sup>12</sup> G, which is within the regime of field strengths considered in recent studies of atoms and molecules in the presence of a strong magnetic field.
Date: March 23, 1999
Creator: Ritchie, A B
Partner: UNT Libraries Government Documents Department

Efficient Inversion of Multi-frequency and Multi-source Electromagnetic Data: Final report

Description: BES grant DE-FG02-06ER15819 supported efforts at Oregon State University (OSU) to develop improved inversion methods for 3D subsurface electromagnetic (EM) imaging. Three interrelated activities have been supported by this grant, and its predecessor (DE-FG02-06ER15818): (1) collaboration with a former student of the PI, Dr. Weerachai Siripunvaraporn (now Professor at Mahidol University in Bangkok, Thailand) on developing and refining inversion methods for 3D Magnetotelluric (MT) data . (2) Development at Oregon State University of a new modular system of computer codes for EM inversion, and initial testing and application of this inversion on several large field data sets. (3) Research on more efficient approaches to multi-transmitter EM inverse problems, to optimize use of expensive data sensitivity calculations needed for gradient based inversion schemes. The last of these activities was the main motivation for this research project, but the first two activities were important enabling steps that produced useful products and results in their own right, including freely avaialable software for 3D inversion of EM geophysical data.
Date: April 10, 2013
Creator: Egbert, Gary D.
Partner: UNT Libraries Government Documents Department

Efficient Inversion of Mult-frequency and Multi-Source Electromagnetic Data

Description: The project covered by this report focused on development of efficient but robust non-linear inversion algorithms for electromagnetic induction data, in particular for data collected with multiple receivers, and multiple transmitters, a situation extremely common in eophysical EM subsurface imaging methods. A key observation is that for such multi-transmitter problems each step in commonly used linearized iterative limited memory search schemes such as conjugate gradients (CG) requires solution of forward and adjoint EM problems for each of the N frequencies or sources, essentially generating data sensitivities for an N dimensional data-subspace. These multiple sensitivities allow a good approximation to the full Jacobian of the data mapping to be built up in many fewer search steps than would be required by application of textbook optimization methods, which take no account of the multiplicity of forward problems that must be solved for each search step. We have applied this idea to a develop a hybrid inversion scheme that combines features of the iterative limited memory type methods with a Newton-type approach using a partial calculation of the Jacobian. Initial tests on 2D problems show that the new approach produces results essentially identical to a Newton type Occam minimum structure inversion, while running more rapidly than an iterative (fixed regularization parameter) CG style inversion. Memory requirements, while greater than for something like CG, are modest enough that even in 3D the scheme should allow 3D inverse problems to be solved on a common desktop PC, at least for modest (~ 100 sites, 15-20 frequencies) data sets. A secondary focus of the research has been development of a modular system for EM inversion, using an object oriented approach. This system has proven useful for more rapid prototyping of inversion algorithms, in particular allowing initial development and testing to be conducted with two-dimensional example problems, ...
Date: March 22, 2007
Creator: Egbert, Gary D.
Partner: UNT Libraries Government Documents Department

Cold Crucible Induction Melter Technology: Results of Laboratory Directed Research and Development

Description: This report provides a review of cold crucible induction melter (CCIM) technology and presents summaries of alternatives and design issues associated with major system components. The objective in this report is to provide background systems level information relating to development and application of cold crucible induction-heated melter technology for radiological waste processing. Included is a detailed description of the bench-top melter system at the V. G. Khlopin Radium Institute currently being used for characterization testing
Date: September 1, 2001
Creator: Gombert, Dirk & Richardson, John Grant
Partner: UNT Libraries Government Documents Department

A Simple Model for Induction Core Voltage Distributions

Description: In fall 2003 T. Hughes of MRC used a full EM simulation code (LSP) to show that the electric field stress distribution near the outer radius of the longitudinal gaps between the four Metglas induction cores is very nonuniform in the original design of the DARHT-2 accelerator cells. In this note we derive a simple model of the electric field distribution in the induction core region to provide physical insights into this result. The starting point in formulating our model is to recognize that the electromagnetic fields in the induction core region of the DARHT-2 accelerator cells should be accurately represented within a quasi-static approximation because the timescale for the fields to change is much longer than the EM wave propagation time. The difficulty one faces is the fact that the electric field is a mixture of both a ''quasi-magnetostatic field'' (having a nonzero curl, with Bdot the source) and a ''quasi-electrostatic field'' (the source being electric charges on the various metal surfaces). We first discuss the EM field structure on the ''micro-scale'' of individual tape windings in Section 2. The insights from that discussion are then used to formulate a ''macroscopic'' description of the fields inside an ''equivalent homogeneous tape wound core region'' in Section 3. This formulation explicitly separates the nonlinear core magnetics from the quasi-electrostatic components of the electric field. In Section 4 a physical interpretation of the radial dependence of the electrostatic component of the electric field derived from this model is presented in terms of distributed capacitances, and the voltage distribution from gap to gap is related to various ''equivalent'' lumped capacitances. Analytic solutions of several simple multi-core cases are presented in Sections 5 and 6 to help provide physical insight into the effect of various proposed changes in the geometrical parameters of the DARHT-2 ...
Date: July 1, 2004
Creator: Briggs, Richard J. & Fawley, William M.
Partner: UNT Libraries Government Documents Department

Campaign to minimize the transverse impedance of the DARHT-2 induction linac cells

Description: This paper discusses the multi-year ''campaign'' to measure and reduce the transverse impedances of the original DARHT-2 accelerator cells in order to limit the beam-breakup instability (BBU) growth through the machine. A series of three prototype cells were designed, modeled, and measured. One of the most important methods for limiting the impedance was the introduction of ferrite absorbers in the oil region immediately upstream of the insulator. When properly tuned in terms of thickness, the effective Q's could be significantly reduced for both the 10 inch ''standard'' cells and the 14 inch ''injector'' cells. We also present a new experimental method (twin lead-loop) to measure the transverse impedance. This method has a number of important advantages over the well-known TSD approach, especially in the low Q regime. For the final prototype standard cell design, we found that Z-perp could be limited to &lt;300 ohms/m with Q's ranging from 3 to 6. There was reasonable agreement between measurements and simulation results from the AMOS code (peak amplitudes within 25-30 percent) with the exception that the resonant mode around 200 MHz had a double-peaked structure that could not be reproduced by simulation.
Date: January 20, 2005
Creator: Briggs, Richard J. & Fawley, William M.
Partner: UNT Libraries Government Documents Department

Design and Formation of a Large, Tetrahedral, Metal-ligand Cluster Using 1,1'-Binaphthyl Ligands

Description: Many chemists have been fascinated with the development of discrete supramolecular structures that encapsulate guest molecules. These structures can be assembled through covalent or hydrogen bonds, electrostatic or metal-ligand interactions. These host structures have provided valuable insight into the forces involved in small molecule recognition. Our work has focused on the design and study of metal-ligand clusters of varying sizes. The naphthalene [M{sub 4}L{sub 6}]{sup 12-} cluster 1, shown in Figure 1, has demonstrated diastereoselective guest binding and chiral induction properties as well as the ability to catalyze reactions carried out inside the cavity in an enzyme-like manner. However, the size of the cavity (ca. 300-500 {angstrom}{sup 3}) has often limited the scope of substrates for these transformations.
Date: March 13, 2008
Creator: Biros, Shannon M.; Yeh, Robert M. & Raymond, Kenneth N.
Partner: UNT Libraries Government Documents Department