| Finite Element Investigation of a Composite Cylindrical Shell Under Transverse Load with through Thickness Shear and Snapping |
DEC 89 |
136 pages |
| Authors:
Kevin J. Silva; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
|
 | The static response of a circular cylindrical open shell (curved panel) constructed of an orthotropic graphite/epoxy laminate is numerically investigated in this thesis. The shell is subjected to an inward point load, centered on and normal to the shell surface, which maintains its original orientation through deformation (i.e. dead load). The shell displacement response is seen to vary widely with shell geometry and boundary conditions, not only in magnitude of ... |
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| A Study of Failure Characteristics in Thermoplastic Composite Laminates Due to an Eccentric Circular Discontinuity |
DEC 89 |
195 pages |
| Authors:
John A. Daniels; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
|
| The purpose of this thesis was to determine (both experimentally and analytically) the initiation and progression of failure, stress-strain response, and the failure loads of Graphite/Polyetheretherketone (Gr/PEEK) laminates, incorporating an eccentric 0.4 inch circular discontinuity, loaded in axial tension at room temperature. For each ply lay-up, three values of eccentricity were considered (the three values of eccentricity were determined by the hole location within each specimen). In addition, experimentation was ... |
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| Theoretical Analysis of Microwave and Millimeter Wave Integrated Circuits |
20 NOV 89 |
21 pages |
| Authors:
J. A. Kong; MASSACHUSETTS INST OF TECH CAMBRIDGE RESEARCH LAB OF ELECTRONICS
|
| The complex resonant frequencies of the open structure of a microstrip antenna consisting of two circular microstrip disks in a three layer stacked configuration have been rigorously calculated as a function of the layered parameters and the ratio of the radii of the two disks. It is shown that for each mode, the stacked circular microstrip structure has dual resonant frequencies which are associated with the two coupled constitutive resonators ... |
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| Nonlinear Modulational Stability and Propagation of an Electromagnetic Pulse in a Two-Component, Neutral Plasma |
10 NOV 89 |
30 pages |
| Authors:
Ronald E. Kates; D. J. Kaup; CLARKSON UNIV POTSDAM NY
|
| Nonlinear effects are studied including possible modulational instability of an intense electromagnetic pulse propagating through a fully- ionized, unmagnetized plasma. The envelope is shown to evolve over long time scales in general according to a vector form of the well-known cubic nonlinear Schroedinger (NLS) equation. Three distinct nonlinear effects contribute terms cubic in the amplitude and thus can be of comparable magnitude: ponderomotive forces, relativistic corrections, and harmonic generation. Influence ... |
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| Apparatus and Method for Locating the Axis of Symmetry (Center of Circular Cross Section) of Three Dimensional Objects. |
07 NOV 1989 |
|
| Authors:
Joseph M. Londino Jr; DEPARTMENT OF THE NAVY WASHINGTON DC
|
 | An apparatus and method for locating the vertical axis of symmetry of a surface of horizontal circular cross-section. The apparatus has a plumb structure that establishes a vertical line of sight, and a horizontal translating structure that preselectedly locates the plumb in the two horizontal dimensions. The plumb has at least three arms whose ends are constrained to lie on a circular perimeter which, because the arms are fixed to ... |
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| Internal Failures in Model Elastomeric Composites |
NOV 89 |
37 pages |
| Authors:
A. N. Gent; Y. C. Hwang; AKRON UNIV OH POLYMER ENGINEERING CENTER
|
| Finite element methods have been used to calculate the rate of release of strain energy caused by growth of an internal crack in some model elastic composites under tension. A layer of a linearly-elastic material was considered, bonded between two flat or two spherical rigid surfaces. The reduction in strain energy caused by a small circular crack at the interface was found to be only about one-half of that due ... |
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| Dual Frequency Launcher for Circularly Polarized Antenna. |
03 OCT 1989 |
|
| Authors:
Ming H. Chen; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| A dual frequency antenna feed is formed from a central, circular waveguide connected to the flat boundry of circular, disk-shaped resonant cavity. A second circular waveguide is connected one end of a disk-shaped resonant cavity. Energy of one frequency enters and exits the cavity along the common axis of the waveguides. Energy of the second frequency is introduced to the same resonant cavity by way of a plurality of bandpass ... |
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| Rectangular-to-Circular Waveguide Transitions for High-Power Circular Overmoded Waveguides |
SEP 89 |
30 pages |
| Authors:
William A. Huting; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| Circular overmoded waveguide is being investigated at The Johns Hopkins University Applied Physics Laboratory (JHU/APL) for low loss, high power microwave transmission near 3.0 GHz. Unfortunately, most microwave rather than overmoded circular waveguide. This problem is usually solved by using metallic waveguide transitions. Design objectives for such transitions include high power carrying capability, low mode conversion, low reflectivity, and low transmission loss. An overview of the theory of waveguide transition ... |
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| Strength Design of Reinforced Concrete Hydraulic Structures: Report 8. Design of Buried Circular Conduits - Flexure and Shear |
SEP 89 |
56 pages |
| Authors:
Stanley C. Woodson; ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS STRUCTURES LAB
|
| A strength design (SD) procedure for buried reinforced concrete circular conduits is presented. The procedure is a combination of results produced through recent work sponsored by the Corps of Engineers and recent studies sponsored by the American Concrete Pipe Association. The SD procedure accounts for both flexure and shear in buried circular conduits subjected to the uniform loading conditions of Engineer Manual 1110-2-2902. Expressions are included that account for the ... |
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| Effect of Organophosphorus Compounds on the Conformation of Acetylcholinesterase and Acetylcholine Receptor |
21 AUG 89 |
|
| Authors:
Jen T. Yang; Chuen-Shang C. Wu; Xi H. Sun; CALIFORNIA UNIV SAN FRANCISCO
|
| Acetylcholinesterase (AChE) from Torpedo californica was purified on acridine affinity columns. The low salt-soluble globular dimer (G2), the tailed asymmetric dodecamer (A12) and its proteolytic tetramer (G4) had similar conformation based on circular dichroism (CD). Each subunit had about 40% alpha- helix, 35% Beta-sheet and 4% Beta-turn. The enzymatic activity was optimal at pH 7-8 and dropped to zero at pH below 5 or above 10. However, the protein was ... |
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| Sentinel Satellite Positional Precision Derived from the NAVSTAR Global Positioning System |
16 AUG 89 |
23 pages |
| Authors:
Michael A. Crombie; ARMY ENGINEER TOPOGRAPHIC LABS FORT BELVOIR VA
|
| Error estimates of position are presented for a variety of symmetric circular satellite constellations when four or five observations are made on NAVSTAR GPS satellites. Results are calculated in terms of minimum PDOP and expected outages. Keywords: Global positioning system; Position dilution of precision; Satellite position precision. (jhd) |
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| Analysis of a TM sub 01 Circular to TE sub 10 Rectangular Waveguide Mode Converter |
AUG 89 |
105 pages |
| Authors:
Joseph R. Mautz; Roger F. Harrington; SYRACUSE UNIV NY DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| A TM sub 01 mode is incident in a circular waveguide in which only the TE sub 11 and TM sub 01 modes can propagate. Two apertures in this circular waveguide feed two rectangular waveguides of identical cross section in which only the TE sub 10 dominant mode can propagate. Close each aperture with perfect conductors. Attempting to restore the original tangential electric field on both sides of each of ... |
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| Strength Design of Reinforced Concrete Hydraulic Structures. Report 9. Analysis and Design of Reinforced Concrete Conduits |
AUG 89 |
109 pages |
| Authors:
Kurt H. Gerstle; Piotr Noakowski; Thomas Rauscher; COLORADO UNIV AT BOULDER DEPT OF CIVIL ENVIRONMENTAL AND ARCHITECTURAL ENGINEE RING
|
| The purpose of this report is to indicate ways of updating current Corps of Engineers specifications for the analysis and design of reinforced concrete culverts. To this end, after reviewing the current state of the art in conduit design, attention is directed to the possibility of including soil- structure interaction in conduit analysis and design. By analysis and example, the beneficial effects of soil-structure interaction are demonstrated. A draft for ... |
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| Electromagnetic Wave Propagation through Circular Waveguides Containing Radially Inhomogeneous Lossy Media |
AUG 89 |
167 pages |
| Authors:
Keith W. Whites; CONSTRUCTION ENGINEERING RESEARCH LAB (ARMY) CHAMPAIGN IL
|
| Propagation characteristics of an electromagnetic (EM) wave inside a waveguide are greatly modified by the introduction of dielectrics into the guide. Frequency of cutoff, attenuation, and power flow distribution are all properties of the EM wave that are highly dependent on the physical structural and composition within the guide. Shielding applications take advantage of the large amount of attenuation provided by a waveguide when the incident EM wave has a ... |
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| Estimation of Extra Drag Force on a Circular Cylinder Due to the Presence of Solid Particles in Subsonic Compressible Flow |
AUG 89 |
|
| Authors:
Stanley B. Mellsen; DEFENCE RESEARCH ESTABLISHMENT SUFFIELD RALSTON (ALBERTA)
|
| The effect of particles, such as dust in air, on aerocynamic drag of circular cylinders was calculated for compressible flow at critical Mach number and for incompressible flow. The effect of compressibility was found negligible for particles larger than about 10 microns, for which the air can be considered a continuum. Drag coefficient and collection efficiency are provided for a wide range of inertia parameters and Reynolds numbers for both ... |
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| Effect of Organophosphorus Compounds on the Conformation of Acetylcholinesterase and Acetylcholine Receptor: Tacrine Protection of Acetylcholinesterase from Inactivation by Diisopropylfluorophosphate and Interaction of Acetylcholinesterase and Acetylcholi |
07 JUL 89 |
|
| Authors:
Jen T. Yang; Chuen-Shang C. Wu; Xihua Sun; CALIFORNIA UNIV SAN FRANCISCO
|
| Tacrine showed an apparent noncompetitive inhibition of actylcholinesterase (AChE) from Torpedo californica with a dissociation constant, K1, of 8.5 nM. It altered the CD bands of AChE in the near-UV region, which monitor the local conformation of aromatic side groups, but not those in the far-UV region, which measure the secondary structure. With this band as a probe, the bound tacrine could be displaced by edrophonium or decamethonium, both of ... |
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| Control of Synthetic Peptide Tertiary Structure |
01 JUL 89 |
3 pages |
| Authors:
Paul B. Hopkins; UNIV OF WASHINGTON SEATTLE DEPT OF CHEMISTRY
|
| The proposed research seeks to design and synthesize large organic molecules possessing precisely defined geometric shapes, A capability which will make possible the design of catalysis and receptors. The approach entails the design of unnatural amino acids which, when incorporated into peptides, will enforce tertiary structure on the overall molecule. Methods are also suggested whereby transiently stable noncovalent complexes of peptides might be permanently stabilized by covalent crosslinking, leading to ... |
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| Human Body Regional Convective Heat Transfer Determination Using Sublimating Naphthalene Disks |
JUL 89 |
22 pages |
| Authors:
K. W. Stephen; Richard R. Gonzalez; Chang Gonzalez; ARMY RESEARCH INST OF ENVIRONMENTAL MEDICINE NATICK MA
|
| The regional convective heat transfer coefficients(hc) on the human body were determined using sublimating naphthalene disks. Circular naphthalene disks were affixed to various body segments of a stationary, life-size manikin, under constant temperature and wind speed in an environmental chamber. The amount of naphthalene weight loss through sublimation was translated to hc using the Chilton-Colburn j-factor analogy between heat and mass transfer. The regional convective heat transfer coefficients can be ... |
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| Focal Plane Antenna Array for Millimeter Waves. |
29 JUN 1989 |
|
| Authors:
William M. Waters; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| A millimeter wave imaging system receives millimeter wave radiation and provides video imaging signals based thereon. The system comprises an imaging lens for receiving incoming radiation; a focal plane antenna array disposed at the focal plane of the lens on which radiation received by the lens is focussed; and signal processing and display circuitry for processing the output of the antenna array and for producing and displaying corresponding video imaging ... |
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| Questionnaire Construction Manual Annex. Questionnaires: Literature Survey and Bibliography |
JUN 89 |
251 pages |
| Authors:
Bettina A. Babbitt; Charles O. Nystrom; ESSEX CORP WESTLAKE VILLAGE CA
|
| This report is an annex to the companion volume, 'Questionnaire Construction Manual,' published in 1985 by the U.S. Army Research Institute for the Behavioral and Social Sciences (ARI). It is designed to present summaries of the latest research findings related to developing questionnaires. Although both volumes were prepared primarily for personnel engaged in developing questionnaires for use in military tests and evaluations, the content is equally applicable to many nonmilitary ... |
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| Fast Array Algorithms for Structured Matrices |
JUN 89 |
2 pages |
| Authors:
Joohwan Chun; STANFORD UNIV CA DEPT OF ELECTRICAL ENGINEERING
|
| Many engineering or mathematical problems require to factorize structured matrices (Toeplitz, Hankel, Vandermonde products of such matrices and their inverses. Schur complements, etc) either in explicit or in disguised form. Consequently there exist various analytic tools regarding structured matrices as well as several fast factorization algorithms. In this thesis, we show that many of these results and several significant generalizations can be obtained in a very constructive way. The genetic ... |
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| Evaluation of the Bistatic Equivalence Theorem for the Near and Far- Field Radar Cross Section of Complex Targets |
JUN 89 |
165 pages |
| Authors:
Charles G. Walls; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
|
| This research examined the applicability of the monostatic-bistatic equivalence theorem (MBET) and associated extensions in determining the extent to which correlation exists between monostatic and bistatic data for both the near and far-field. A secondary objective was to determine whether reliable bistatic near-field radar cross section (RCS) data could be collected on a range originally designed to take monostatic far-field measurements. Dr. David Falconer developed two extensions of the MBET ... |
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| Slotted-Waveguide Amplifiers for Millimeter Waves |
10 MAY 89 |
25 pages |
| Authors:
S. T. Smith; NAVAL RESEARCH LAB WASHINGTON DC
|
| Slotted waveguides and ribbon electron beams are studied as electron- beam interaction circuits instead of the usual circular-beam devices. The slotted waveguide and ribbon beam can be many wavelengths long, and therefore the effective beam cross-sectional area is greatly increased over that of the circular beam helix, coupled-cavity or kylstron tubes. This increased beam area results in more beam current, more beam power, and less stringent requirements on cathode current ... |
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| Theoretical Analysis of Microwave and Millimeter Wave Integrated Circuits Based on Magnetic Films |
31 MAR 89 |
|
| Authors:
J. A. Kong; MASSACHUSETTS INST OF TECH CAMBRIDGE RESEARCH LAB OF ELECTRONICS
|
| The complex resonant frequencies of the open structure of a microstrip antenna consisting of two circular microstrip disks in a three layer stacked configuration have been rigorously calculated as a function of the layered parameters and the ratio of the radii of the two disks. Using a dyadic Green's function formulation for horizontally stratified media and the vector Hankel transform, the mixed boundary value problem is reduced to a set ... |
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| Three Dimensional Equilibrium and Stability of Ionospheric Plasma Clouds |
22 MAR 89 |
67 pages |
| Authors:
J. F. Drake; M. Mulbrandon; J. D. Huba; NAVAL RESEARCH LAB WASHINGTON DC
|
| The equilibrium and stability of three dimensional ionospheric plasma clouds is investigated. The equilibrium density profile is assumed to be a 3D waterbag with a circular cross-section transverse to B, and an ellipsoidal cross-section parallel to B. The equilibrium potential consists of two parts: a polarization potential driven by a uniform neutral wind, and an ambipolar potential driven by parallel electron pressure. The latter potential is shown to cause sheared ... |
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| Some Ray Tracing Problems Related to Circles and Ellipses |
MAR 89 |
47 pages |
| Authors:
Henning Bach; ROME AIR DEVELOPMENT CENTER GRIFFISS AFB NY
|
| A classical ray tracing problem, namely the celebrated Alhazen Mirror Problem, is reviewed. An alternative formulation of the law of reflection, leading, in the spherical mirror case, directly to Alhazen's equation is presented. The locus method of ray tracing is introduced and applied to Alhazen's problem. Finally, the technique is applied to some ray tracing problems, which often occur in practice, namely reflection by a circular cylinder and diffraction by ... |
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| On Specimen Shape Effects and the Ductility of Porous Metals |
FEB 89 |
24 pages |
| Authors:
A. Geltmacher; D. A. Koss; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF MATERIALS SCIENCE AND ENGINEE RING
|
| The influence of specimen shape on the elongation to failure has been simulated for materials containing random distributions of pores or voids. The analysis is performed utilizing a computer simulation in which distributions of pores are modeled in two dimensions as arrays of circular holes with differing hole microstructures . The simulations predict that long, narrow specimens with high aspect ratios should exhibit a loss of ductility which is most ... |
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| Numerical Conformal Mapping and Applications |
18 JAN 89 |
15 pages |
| Authors:
Lloyd N. Trefethen; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF MATHEMATICS
|
| Progress was made in three principal areas: (1) Conformal mapping of highly elongated polygons. Conventional methods of conformal mapping break down when applied to highly distorted regions, as arise frequently in applications. In the first year of research under this grant, Prof. Trefethen and Louis Howell developed a modified Schwarz-Christoffel formula to handle highly elongated polygons. In the second year this work was completed and written up for publication in ... |
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| Characterization by NMR and Fluorescence Spectroscopy of Differences in the Conformation of Non-Aged and Aged Organophosphoryl Conjugates of AChE (acetylcholinesterase) |
01 JAN 89 |
29 pages |
| Authors:
Y. Ashani; I. Silman; ISRAEL INST FOR BIOLOGICAL RESEARCH NESS ZIONA
|
| The objective of this project is to detect and characterize, by NMR and fluoressence spectroscopy, differences in the conformation of non-aged and aged organophosphoryl (OP) conjugates of acetylcholinesterase (AChE) and chymotrypsin (Cht). During the period covered by this report, we developed a synthetic procedure to obtain a novel OP which contained the fluorophore, 2- hydroxynaphthol and showed that it could be employed as a covalent inhibitor of both AChE and ... |
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| Oblique and Parallel Modes of Vortex Shedding in the Wake of a Circular Cylinder at Low Reynolds Numbers |
89 |
50 pages |
| Authors:
C. H. Williamson; CALIFORNIA INST OF TECH PASADENA GRADUATE AERONAUTICAL LABS
|
| Two fundamental characteristics of the low-Reynolds-number cylinder wake, which have involved considerable debate, are first the existence of discontinuities in the Strouhal-Reynolds number relationship, and secondly the phenomenon of oblique vortex shedding. The present paper shows that both of these characteristics of the wake are directly related to each other, and that both are influenced by the boundary conditions at the ends of the cylinder, even for spans of hundreds ... |
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| Scattering of Flexural Waves by Cavities in a Plate |
89 |
15 pages |
| Authors:
R. Paskaramoorthy; A. H. Shah; S. K. Datta; COLORADO UNIV AT BOULDER
|
| In this reprint, the scattering of slow flexural waves by arbitrary shaped cavities in an infinite elastic plate is studied using a combined finite element and analytical method. The problem is considered as consisting of two interacting systems, a bounded interior region containing all material and geometric irregularities, and an unbounded exterior region. The interior region is modelled by using Mindlin type plate bending elements. Wave function expansion is used ... |
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| Elasticity Effects on Cavitation in a Squeeze Film Damper Undergoing Noncentered Circular Whirl |
89 |
20 pages |
| Authors:
David E. Brewe; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH LEWIS RESEARCH CEN TER
|
| Elasticity of the linear and its effects on cavitation were numerically determined for a squeeze film damper subjected to dynamic loading. The loading was manifested as a prescribed motion of the rotor undergoing noncentered circular whirl. The boundary conditions were implemented using Elrod's algorithm which conserves lineal mass flux through the moving cavitation bubble as well as the oil film region of the damper. Computational movies were used to analyze ... |
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| Radio Frequency Plasma Generator. |
20 DEC 1988 |
|
| Authors:
James P. O'Loughlin; DEPARTMENT OF THE AIR FORCE WASHINGTON DC
|
| A plasma generator for exciting electrons in the plasma to a uniform energy level. In a preferred embodiment, two sets of mutually perpendicular electrodes surround a container of gas, with one set being driven through a ninety degree phase shifter to establish a circularly polarized field in the space within the container. Alternative means are disclosed for launching circularly polarized RF waves into the container of gas. A desired level ... |
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| A New Model for the Forced Response of a Mistuned Disk |
DEC 88 |
100 pages |
| Authors:
Jeffrey S. Turcotte; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
|
| A simple model is developed for the forced response of a mistuned, center-clamped disk to predict experimental observations. The response near a resonance can take the form of rotating node lines. A simple model of a mistuned stationary disk was developed and the transverse responses to both rotating point loads and stationary point loads oscillating in time were determined. The disk model uses torsional springs applied at points on the ... |
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| Analysis of Turbulent Boundary-Layer over Rough Surfaces with Application to Projectile Aerodynamics |
DEC 88 |
63 pages |
| Authors:
James E. Danberg; Asher Sigal; ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| A new correlation of the roughness density effect on the intercept of the law of the wall and the equivalent sand roughness, has been developed. The data base used includes corrected results of Schlichting's rough channel experiment and those of twelve other studies. The roughness density parameter used is a product of the reference surface to the total frontal area ratio and a shape factor. For two dimensional roughness, the ... |
|
| The Cerenkov Free-Electron Laser |
22 NOV 88 |
51 pages |
| Authors:
John E. Walsh; DARTMOUTH COLL HANOVER N H DEPT OF PHYSICS
|
| In the Cerenkov free-electron laser experiments, dielectric-loaded quasi-optic resonators were used to couple the electron beam to the electromagnetic field. Three types of electron beam generators were employed: a pulse-transformer-based modulator (which operates in the 50-250 KV range), a Marx generator (which operated in the 500 kv - 1.1 MV range), and a circular RF accelerator (microtron) operating at 5 Mev. The pulse-transformer-based system was used primarily for mm-wavelength experiments. ... |
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| Compact Microstrip Latching Reciprocal Phase Shifter. |
23 OCT 1988 |
|
| Authors:
Richard A. Stern; Richard W. Babbitt; DEPARTMENT OF THE ARMY WASHINGTON DC
|
| A latching type of microstrip reciprocal phase shifter is provided having a toroidal-shaped ferrite core with a length of microstrip conductor wound about the outer cylindrical surface of the core and a ground plane mounted on the inner cylindrical surface of the core and a ground plane mounted on the inner cylindrical surface of the core surrounding the aperture in the core. A single control wire is passed through the ... |
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| Very Large Array Observations of the Sun with Related Observations Using the SMM (Solar Maximum Mission) Satellite |
12 OCT 88 |
327 pages |
| Authors:
Kenneth R. Lang; TUFTS UNIV MEDFORD MA DEPT OF PHYSICS AND ASTRONOMY
|
| Multiple Wavelength Observations of Flaring Active Regions; Very Large Array Observations of Solar Active Regions III. Multiple Wavelength Observations. High-Resolution Observations of Solar Radio Bursts at 2, 6, and 20 cm Wavelength; The Circularly Polarized Sun at 12.6 cm Wavelength; Bright, Rapid, Highly Polarized Radio Spikes from the M Dwarf AD. Leonis; Possible Detection of Thermal Cyclotron Lines from Small Sources within Solar Active Regions. Observations of Preburst Heating and ... |
|
| A Study of an Intense Density Front in the Eastern Alboran Sea: The Almeria-Oran Front |
OCT 1988 |
17 pages |
| Authors:
J. Tintore; P. E. La Violette; I. Blade; A. Cruzado; NAVAL OCEAN RESEARCH AND DEVELOPMENT ACTIVITY STENNIS SPACE CENTER MS
|
| Studies of satellite imagery and space shuttle photographs of the western Mediterranean have indicated that the main path of inflowing Atlantic Water is around two large anticyclonic gyres in the Alboran Sea and along the Algerian Coast. These studies have also shown that a strong ocean front is present between Almeria, Spain, and Oran, Algeria, which is part of the easternmost segment of the Eastern Alboran Gyre. Based on these ... |
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| Novel Methods of Acceleration. |
29 SEP 1988 |
19 pages |
| Authors:
John A. Nation; CORNELL UNIV ITHACA NY
|
| A full cusp diode geometry and fast puff valve system have been developed for the proton linac experiment. After passing through the first gap section, a transport efficiency of 99% has been achieved. Microwave input mode stability has been tested on a rectangular cross-section undulating guide accelerator cavity. Switching to a circular cross-section would appear to have certain advantages. Keywords: Plasma accelerators; Linear accelerators. (jhd) |
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| Investigating the Structural Bases of Voltage-Gating Model Channels by Using Perfectly Aligned Multilayer Samples |
20 SEP 88 |
8 pages |
| Authors:
Huey W. Huang; RICE UNIV HOUSTON TEX DEPT OF PHYSICS
|
| One dimensional quasi crystals of perfect multilayers, in which ion channels are uniformly oriented within parallel membranes, can be used to study the structural base of channel conductivities. We have developed 1) the techniques for preparing such multilayer samples and 2) the spectroscopic methods (circular dichroism and x-ray diffraction) for extracting structural information from these samples. The sample variables include electric field, water content, ion concentrations, etc. We have observed ... |
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| The Modeling of Viscoelastic Circular Plates for Use as Waveguide Absorbers |
SEP 88 |
211 pages |
| Authors:
Charles D. Hettema; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The need exists to reduce structural vibrations in plates, such as ship's hulls. It was proposed to use waveguide absorbers as a means to reduce structural vibrations. A waveguide absorber is a device which is made from damping material but mounted to the structure at a point rather than the full surface. A waveguide absorber removes and then dissipates vibrational energy from the structure through traveling waves. The performance of ... |
|
| Strength Design of Reinforced Concrete Hydraulic Structures. Report 7. Strength of Circular Reinforced Concrete Conduits, Analysis and Design |
SEP 88 |
105 pages |
| Authors:
Kurt H. Gerstle; COLORADO UNIV AT BOULDER DEPT OF CIVIL ENVIRONMENTAL AND ARCHITECTURAL ENGINEE RING
|
| Various analytical and experimental aspects of the US Army Engineer Waterways Experiment Station concrete pipe test program were studied in an effort to maximize the returns from this project. Methods of flexural strength prediction, based on both elastic and plastic approaches, are presented and applied to the test specimens. Different approaches to determination of flexural strength are critically discussed, and the applicability of each approach is checked by comparison with ... |
|
| Triple Frequency U-Slot Microstrip Antenna. |
23 AUG 1988 |
|
| Authors:
Michael J. Gegan; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| A microstrip antenna employing a rectangular radiating element having a U-shaped slot oriented parallel to the length of the radiating element and employing a single feedline coplanar with the radiating element. The slotted radiating element has three resonances: a length resonance polarized parallel to the length of the element; a width resonance polarized parallel to the width element; and a slot resonance polarized parallel to the length of the element. ... |
|
| Numerical Evaluation of a Solution Representing a Jet in Cross-Flow |
AUG 88 |
51 pages |
| Authors:
C. C. Lytton; J. H. Smith; ROYAL AEROSPACE ESTABLISHMENT FARNBOROUGH (ENGLAND)
|
| A recent study of a jet emerging from a circular pipe into a weak cross flow under the assumptions of an inviscid and incompressible fluid led to expressions for the velocity potential in different regions near the orifice as definite integrals and infinite sums. In the present paper the expressions relating to flow inside the pipe and jet are evaluated with great care. It is confirmed that the solutions in ... |
|
| Tuning Stability of a Digitally-Tuned, Electrically-Short Monopole Element Mounted on Circular Groundplanes of Different Radii |
AUG 88 |
65 pages |
| Authors:
M. M. Weiner; MITRE CORP BEDFORD MA
|
| Double and single parameter tuning of a digitally tuned, electrically short monopole antenna at the center of a circular groundplane is investigated to determine the range of groundplane radii for which the same tuning words can be utilized in maintaining a specified antenna gain over a given frequency band. It is found that the range of groundplane radii is generally not significantly larger with double parameter tuning than with single ... |
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| GPS (Global Positioning System) User Equipment Evaluation Techniques Using a Rotor Mounted Antenna |
AUG 88 |
20 pages |
| Authors:
J. S. Gubbay; SURVEILLANCE RESEARCH LAB SALISBURY (AUSTRALIA)
|
| The accuracy of the NAVSTAR Global Positioning System (GPS) permits evaluation of dynamic performance of user equipments by mounting the antenna on a rotor of practical dimension. The reported diameter of the circular path described by the antenna phase centre will depend on Kalman filter characteristics and will tend Rayleigh statistics through measurement delay intervals up to 1 min. This characteristic of system noise and the development of symmetry techniques ... |
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| The Behavior of Microdisk and Microring Electrodes. The Chronoamperometric Response at Microdisk and Microring Electrodes |
15 JUL 88 |
24 pages |
| Authors:
L. J. Li; M. Hawkins; J. W. Pons; M. Fleischmann; S. Pons; UTAH UNIV SALT LAKE CITY DEPT OF CHEMISTRY
|
| We report the theoretical chronoamperometric response for a ring electrode of finite size, and compare the experimental response to that of a disk electrode. As expected, the response of the ring electrode approaches mass transport conditions close to those for the final steady state at times which are short compared to those at which the steady state is reached for disks of similar radii. The theoretical analysis is based on ... |
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| The Behavior of Microdisk and Microring Electrodes. Mass Transport to the Disk in the Unsteady State: Chronopotentiometry |
15 JUL 88 |
24 pages |
| Authors:
Stanley Pons; M. Fleischmann; UTAH UNIV SALT LAKE CITY DEPT OF CHEMISTRY
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| We describe the time dependent response of a finite disk electrode under conditions of constant applied flux (chronopotentiometry). The exact solution is recovered by solving the differential equations in the circular cylindrical coordinate system with the use of suitable discontinuous integrals. In addition, we present the results for the case of linear sweep amperometry, which will generally be more useful for controlled current experiments with microelectronics. Keywords: Microelectronics; Reprints. (KT) ... |
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| Corrosion Measurements Using Microelectrodes |
08 JUL 88 |
33 pages |
| Authors:
Kazimierz Wikiel; Janet Osteryoung; STATE UNIV OF NEW YORK AT BUFFALO DEPT OF CHEMISTRY
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| It is shown microelectrodes can be substituted for large area area electrodes in typical corrosion measurements. Results obtained for copper and iron in concentrated solutions are consistent with earlier literature report. Application of microelectrodes markedly reduces effects of IR-ohmic drops. It allows one to apply electrochemical methods in corrosion investigations under conditions closer to those of natural corrosion environments. The corrosion rate of circular copper microelectrodes in 0.1 mol/dm 3 ... |
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