N91-12308# Tennessee Univ., Knoxville. Dept. of Psychology. MODIFICATIONS OF THE TEST INFORMATION FUNCTION Technical Report, 1987 - 1990 Fumiko Samejima 30 Jun. 1990 39 p (Contract N00014-87-K-0320; NR Proj. RR0-4204) (AD-A224698; ONR-RR-90-1) Avail: NTIS HC/MF A03 CSCL 12/3 A minimum bound of any estimator, biased or unbiased, is considered, and, based on that, Modification Formula No. 1 is proposed for the maximum likelihood estimator, in place of the test information function. A minimum bound of the mean squared error is considered, and, based on that, Modification Formula No. 2 in the same context is proposed. Examples are given, and the usefulnesses of these modified test information functions in computerized adaptive testing are discussed. These topics are also discussed and observed for the monotonically transformed latent variable. GRA N91-12309# Army Armament Munitions and Chemical Command, Rock Island, IL. Systems Analysis Office. STATISTICAL DECISIONS UTILIZING NEURAL NETS Memorandum Report, Jan. - Mar. 1990 Jack Manata and George Schlenker 30 May 1990 48 p (AD-A224752; AMSMC/SA-MR-9004) Avail: NTIS HC/MF A03 CSCL 12/3 Neural networks were developed that accurately determine the statistical characteristics: modality and number of stochastic components of underlying probability distribution(s) for sample data. Sample data examples, used to teach the neural nets were generated utilizing either a single beta distribution or a mixture of beta distributions. Once the neural net learned to distinguish between unimodal and multimodal examples and also between unimodal and mixture densities, they were challenged with unknown test cases. The test cases were also generated from either a single beta distribution or a mixture of beta distributions. Therefore the initial test results apply to a restricted class of distributions having bounded domains. The initial testing of the neural networks consisted of 40 unknown sample data examples generated utilizing beta distributions. The results of these tests are: (1) correctly identified 39 out of the 40 as being either unimodal or multimodal, an accuracy of 97.5 percent. This exceeds the accuracy of currently available statistical methods; (2) correctly identified 36 out of 40 as having either one component or more than one component, an accuracy of 90 percent. GRA GOODNESS OF FIT TESTS AND ENTROPY (AD-A224860; TR-103; ARO-27574.2-MA) Avail: NTIS HC/MF A03 CSCL 12/3 The unifying role of entropy statistics and concepts is discussed in developing goodness of fit tests for a parametric model F(x;Theta) for a continuous distribution function F(x), given a random sample from the distribution F. Statistics discussed are those by Moran (extended by Cheng and Stephens), Vasicek and Dudewicz and van der Meulen (based on gap estimators of quantile density function), Parzen (autoregressive estimators of quantile density functions), and shapiro and Wilk. They are given unified formulations as entropy difference statistics. Their 95 percent significance levels for sample sizes 20 and 50 are compared and shown to increase as amount of smoothing decreases. GRA (Brunswick, Fed. Republic of Germany, DFVLR), Dec. 1988 31 p Original language document was announced as N89-26666 (ESA-TT-1152; DFVLR-Mitt-88-34; ETN-90-98006) Avail: NTIS HC/MF A03 A Monte Carlo formula is propsed for statistical cases with unknown test distribution. The hypothetical model is used to simulate a certain number of measurement series for which there applies the hypothesis which must accordingly be tested, calculating the corresponding simulated test variable values of actual observations. A substitute hypothesis is examined. The formal facilities for application of significance tests in systems identification are set. ESA This report recounts the progress the SDI program has made over the last several years and describes our plans for the future. One of the biggest breakthroughs occurred recently: the introduction of the Brilliant Pebbles concept into the space-based portion of the defense architecture. Preliminary cost estimates and effectiveness analyses indicate that deployment of Brilliant Pebbles as the space-based layer of a Phase One Strategic Defense System could allow savings of $14 billion from previous estimates, reducing the cost of an initial system from $69 billion to approximately $55 billion. In 1989, we launched the Beam Experiment Aboard a Rocket (BEAR), which demonstrated propagation of a particle beam in space. Also in 1989, we witnessed the first firing of the Alpha chemical laser. In 1990, we plan to achieve even more significant testing milestones. In January, we launched the first High Endo-Atmospheric Defense Interceptor (HEDI) test and demonstrated the ability to cool the interceptor's forebody and sensor window. We are demonstrating defensive technologies that we believe offer the potential for moving toward a more stable relationship with the Soviet Union while reducing offensive forces. In sum, our efforts to demonstrate defensive technologies, to modernize our offensive forces and to work toward beneficial arms control agreements are fully integrated and mutually reinforcing. GRA N91-12313# Pittsburgh Univ., PA. Learning Research and Development Center. ADAPTIVE SEARCH THROUGH CONSTRAINT VIOLATIONS Stellan Ohlsson and Ernest Rees Jan. 1990 25 p Sponsored in part by Xerox Corp. (Contract N00014-89-J-1681; NR Proj. RR0-4206) HC/MF A03 CSCL 12/4 Restructuring consists of a change in the representation of the current search state, a process which breaks an impasse during problem solving by opening up new search paths. A corpus of 52 think-aloud protocols from the domain of geometry was scanned for evidence of restructuring. This data suggest that restructuring is accomplished by re-parsing the geometric diagram. GRA N91-12315*# National Aeronautics and Space Administration. WAKE GEOMETRY EFFECTS ON ROTOR BLADE-VORTEX R. M. Martin, Michael A. Marcolini, W. R. Splettstoesser, and K.-J. (NASA-TP-3015; L-16723; NAS 1.60:3015) Avail: NTIS HC/MF A03; 6 functional color pages CSCL 20A Acoustic measurements from a model rotor wind tunnel test are presented which show that the directionality of rotor blade vortex interaction (BVI) noise is strongly dependent on the rotor advance ratio and disk attitude. A rotor free wake analysis is used to show that the general locus of interactions on the rotor disk is also strongly dependent on advance ratio and disk attitude. A comparison of the changing directionality of the BVI noise with changes in the interaction locations shows that the strongest noise radiation occurs in the direction of motion normal to the blade span at the time of interaction, for both advancing and retreating side BVI. For advancing side interactions, the BVI radiation angle down from the tip-path plane appears relatively insensitive to rotor operating condition and is typically between 40 and 55 deg below the disk. However, the azimuthal radiation direction shows a clear trend with descent speed, moving towards the right of the flight path with increasing descent speed. The movement of the strongest radiation direction is attributed to the movement of the interaction locations on the rotor disk with increasing descent speed. N91-12316*# Author National Aeronautics and Space Administration. Lewis Research Center, Cleveland, OH. NEAR-FIELD NOISE OF A SINGLE-ROTATION PROPFAN AT AN ANGLE OF ATTACK M. Nallasamy, E. Envia (Sverdrup Technology, Inc., Brook Park, OH.), B. J. Clark, and J. F. Groeneweg Oct. 1990 20 P Presented at the 13th Aeroacoustics Conference, Tallahassee, FL, 22-24 Oct. 1990; sponsored in part by AIAA (NASA-TM-103645; E-5805; NAS 1.15:103645; AIAA-90-3953) Avail: NTIS HC/MF A03 CSCL 20A The near field noise characteristics of a propfan operating at an angle of attack are examined utilizing the unsteady pressure field obtained from a 3-D Euler simulation of the propfan flowfield. The near field noise is calculated employing three different procedures: a direct computation method in which the noise field the is extracted directly from two Euler solution, and acoustic-analogy-based frequency domain methods which utilize the computed unsteady pressure distribution on the propfan blades as the source term. The inflow angles considered are -0.4, 1.6, and 4.6 degrees. The results of the direct computation method and one of the frequency domain methods show qualitative agreement with measurements. They show that an increase in the inflow angle is accompanied by an increase in the sound pressure level at the outboard wing boom locations and a decrease in the sound pressure level at the (inboard) fuselage locations. The trends in the computed azimuthal directivities of the noise field also conform to the measured and expected results. Author N91-12317*# National Aeronautics and Space Administration. Lewis Research Center, Cleveland, OH. Sep. EMERGING APPLICATIONS OF HIGH TEMPERATURE SUPERCONDUCTORS FOR SPACE COMMUNICATIONS Vernon O. Heinen, Kul B. Bhasin, and Kenwyn J. Long 1990 12 P Presented at the World Congress on Superconductivity, Houston, TX, 10-13 Sep. 1990 (NASA-TM-103629; E-5797; NAS 1.15:103629) Avail: NTIS HC/MF A03 CSCL 20A Proposed space missions require longevity of communications system components, high input power levels, and high speed digital logic devices. The complexity of these missions calls for a high data bandwidth capacity. Incorporation of high temperature into superconducting (HTS) thin films some of these communications system components may provide a means of meeting these requirements. Space applications of superconducting technology has previously been limited by the requirement of cooling to near liquid helium temperatures. Development of HTS materials with transition temperatures above 77 K along with the natural cooling ability of space suggest that space applications may lead the way in the applications of high temperature superconductivity. In order for HTS materials to be incorporated into microwave and millimeter wave devices, the material properties such as electrical conductivity, current density, surface resistivity and others as a function of temperature and frequency must be well characterized and understood. The millimeter wave conductivity and surface resistivity were well characterized, and at 77 K are better than copper. Basic microwave circuits such as ring resonators were used to determine transmission line losses. Higher Q values than those of gold resonator circuits were observed below the transition temperature. Several key HTS circuits including filters, oscillators, phase shifters and phased array antenna feeds are feasible in the near future. For technology to improve further, good quality, large area films must be reproducibly grown on low Author dielectric constant, low loss microwave substrates. N91-12318# Texas Univ., Austin. Applied Research Lab. (AD-A224738; ARL-TR-90-21) Avail: NTIS HC/MF A03 CSCL 20/1 Propagation in a periodic waveguide is a combined theoretical and experimental study of acoustic Bloch waves in a rectangular, air filled waveguide that is periodically loaded with reactive branch elements. Second harmonic distortion was investigated. A quasilinear solution of the generalized Westervelt equation, with certain terms neglected, showed that although the fundamental Bloch wave is progressive, the second harmonic Bloch wave has both forward traveling and backward traveling components. Experimental measurements generally confirmed the theoretical predictions. Scattering of sound by sound was studied by analysis of the effect of various source boundary conditions on the scattered field. The project is mainly experimental, however. The tank facility where the experiments on scattering will be carried out, was completed. A series of three different experiments is planned. Some work was also done on an upgrade of the Nonlinear Acoustics Lab and measurements of ellipsoidal focusing of spark produced N waves. GRA N91-12319# David Taylor Research Center, Bethesda, MD. Dept. of Propulsion and Auxiliary Systems. USE OF RADIATION EFFICIENCY IN NOISE CONTROL J. Dickey, G. Maidanik, and J. Ertel (Naval Academy, Annapolis, (AD-A225054; DTRC-90/019) Avail: NTIS HC/MF A03 CSCL 20/1 The radiation efficiency is defined in terms of the power that is radiated by a structure, the absolute square of the normal velocity on the surface integrated over that surface, and the characteristic impedance of the fluid facing the surface. The utilization of the radiation efficiency as a useful engineering quantity for describing the radiation from panel-like structures and for the estimation of the effectiveness of measures that may be used to control the radiated power from such structures is questioned. Caution needs to be exercised in the use of the radiation efficiency for these purposes. GRA (Contract N00014-85-K-0701) (AD-A225190) Avail: NTIS HC/MF A03 CSCL 09/1 The goals of this project involve the development and application of new techniques in acoustics. The goals are: (1) to study the properties of single crystal high temperature superconductor oxide materials with ultrasonic measurements; (2) to study the properties of quasicrystals using ultrasound and acoustic analog systems; and (3) to develop and apply a new resonant photo-acoustic technique to measure optical absorption in very low-loss glasses and crystals. Major accomplishments include the development of a new method of ultrasound elastic constants of very small samples (a few hundred microns in size), and the development and test of a new technique for measuring optical absorption with more than an order of magnitude improvement in sensitivity over existing methods. N91-12321# European Space Agency, Paris (France). BULK ACOUSTIC WAVE RESONATORS MADE OF AMORPHOUS MATERIALS GRA Michel Breuzet (Office National d'Etudes et de Recherches Aerospatiales, Paris, France) Aug. 1990 202 p Transl. into ENGLISH of Resonateurs a Ondes Elastiques de Volume en Materiaux Amorphes (Paris, France, ONERA), 1989 165 p Original language document was announced as N90-17416 (ESA-TT-1201; ONERA-NT-1989-1; ETN-90-98012) Avail: NTIS HC/MF A10 The investigation of plates vibrating at radio frequency and made of amorphous conductive or insulating materials is carried out. Capacitive excitation was employed for this type of resonator made of non piezoelectric material. The advantage of using contour vibration modes is demonstrated, with particular reference to the Lame mode. The optimization of mountings designed to minimize resonator/mounting coupling is investigated. The finite element computing method was applied. The results obtained on resonators made of AU4G and vitreous silica (SiO2) are discussed. ESA N91-12322# Institut Franco-Allemand de Recherches, Saint-Louis (France). NOISE PREDICTION FOR A THREE-DIMENSIONAL M. Schaffar, J. Haertig, and P. Gnemmi 19 Jul. 1990 15 p Presented at Euromech Colloquium 247, Goettingen, Fed. Republic of Germany, 28 Jun. 1 Jul. 1989 (ISL-CO-226/89; ETN-90-98035) Avail: NTIS HC/MF A03 The vortex lattice method is described and applied in order to predict the aerodynamic loads on a thin one-bladed rotor. A local conformal mapping for each position in span is used to transform the thin blade into a thick one. The pressure coefficients obtained for the thick blade are fed into an acoustic code which is based on Ffowcs-Williams-Hawkings equation. For a first calculation, the blade vortex interaction is simplified: the wake shedded by the previous blades is contracted into a vortex line and the interaction occurs near an azimuth angle of 40 degrees (advancing blade). The calculated noise shows that the horizontal directively has a maximum in the forward direction and the computed pressure signatures are very similar to the measured signatures found in the literature. ESA N91-12323# Technical Research Centre of Finland, Espoo. Lab. of Heating and Ventilation. ANALYSIS METHODS FOR ACOUSTICAL SYSTEMS BASED ON THE FFT AND INTENSITY TECHNIQUES Ph.D. Thesis Tapio Lahti Aug. 1990 293 p Sponsored by Finnish Foundation of Technology (VTT-67; ISBN-951-38-3760-2; ISSN-0358-5069; ETN-90-98233) Copyright Avail: NTIS HC/MF A13; Governement Printing Center, P.O. Box 516, SF-00101 Helsinki, Finland, HC 170 Finnish marks A two part study on the measurement and analysis of acoustical systems is presented, consisting of the development of various methods based on the Fast Fourier Transform (FFT) and intensity, and a collection of experiments for testing their applicability. The measurements were made with a dual channel FFT analyzer, and the 2-D space-wavenumber FFT is used in some subsequent analyses. Most of the methods and experiments are related to the two transducer sound intensity techniques. The presented methods extend possibilities available for investigating more complicated acoustical systems such as the window. ESA Qian Niu Aug. 1990 59 p Submitted for publication (Contract N00014-89-J-1530) (AD-A224658; TR-31) Avail: NTIS HC/MF A04 CSCL 20/12 This work deals with the quantum dynamics of a narrow band particle interacting with phonons and static disorder. The present theory is exact in the limit of small band width compared with the Debye energy, and covers various regimes in the parameter space of temperature and disorder strength. Therefore, the theory provides a unified framework for studying when and how the particle motion changes from coherent band like behavior to incoherent hopping, as the temperature and/or disorder strength are increased. The theory also includes the double well problem as a special case, where rather complete description of the particle motion is obtained. GRA N91-12325# Harry Diamond Labs., Adelphi, MD. MOBILITY OF NONEQUILIBRIUM CONDUCTION ELECTRONS IN AIR Final Report, Oct. 1988 - Sep. 1989 William T. Wyatt, Jr. and Christopher S. Kenyon Jun. 1990 51 p Sponsored by Army Lab. Command, Adelphi, MD (AD-A224909; HDL-TR-2184) Avail: NTIS HC/MF A04 CSCL 20/9 An integro-differential equation is derived describing the time evolution of the electron energy distribution function in a gas in a transient electric field. A finite difference approximation and a time stepping algorithm using matrix-vector techniques are devised to solve the integro-differential equation. An extensive published cross section set is added to the time stepping algorithm, enabling one to calculate realistic energy distribution functions in air. Also described is a projection method that allows computation of electron swarm properties such as collision volume (inversely related to mobility) using measured data for equilibrium distributions. This projection method is shown to have desirable variational properties in calculating the swarm properties. Compare orthogonal and nonnegative projection methods with conventional techniques for their ability to reduce error in estimates of collision volume arising from cross section induced error in the energy distribution function. A single-vector projection with cleanup of approximation error performs best, leading to significant reduction of collision volume error when the distribution function maximum occurs at not more than about 0.1 eV. Other projections perform poorly compared to conventional methods of calculating swarm collision volume, because of inherent dependence of the projection basis of equilibrium distributions and resulting ill-conditioning of the projection matrix. GRA N91-12326# Maryland Univ., College Park. Dept. of Electrical Engineering. INVESTIGATION OF THE PROPAGATION OF INTENSE William W. Destler Jul. 1990 128 p Laser-controlled beamfront accelerator experiments achieved gradients of up to 40 MV/m and proton acceleration to 18 MeV over 40 cm with a beam energy of 900 keV. Beamfront electric field degradation requirements beam energy to be increased as the gradient is increased. An experiment with a beam energy of 1.5 MeV achieved a 60 MV/m gradient in a 100 cm distance, matching theoretical models. Experiments with pseudospark discharges achieved electron beams of 25 kV, 1000 A/sq cm, 10 ns with 10(11) A/sq(m-rad) brightness. Theory indicates densities (DE91-000238; LA-UR-90-3127; CONF-9008161-1) Avail: NTIS HC/MF A02 The effect of surface roughness on the specular intensity of a reflected neutron beam can be calculated using the distorted wave Born approximation. For Gaussian roughness the result obtained is the familiar expression of Nevot and Croce. When the distribution of surface heights, z, is proportional to cosh/2(z/2d), the calculated reflectance is sinh(pi d k sub 0 -k sub 1)/ sinh(pi d k sub 0 +k sub 1). Here k sub 0 and k sub 1 are the components of neutron wavevectors perpendicular to the interface, evaluated outside and inside the reflecting medium, and d is a measure of the amplitude of the roughness. This result for the reflectance differs by a phase factor from that obtained in an exact calculation for an interface with the corresponding graded refractive index. The phase difference between the two expressions is small, scaling as approx. d sup 3, and usually has little effect on measured reflectivities of multilayered structures. Ways in which the phase could be determined are discussed. DOE N91-12328# New Mexico State Univ., Las Cruces. (Contract DE-FG04-88ER-40403) This report summarizes the work on experimental research in intermediate energy nuclear and particle physics carried out by New Mexico State University in 1988 to 1991. Most of these studies have involved investigations of neutron-proton and pion-nucleus interactions. The neutron-proton research is part of a program of studies of interactions between polarized nucleons which has continued for more than ten years. Its purpose was to help complete the determination of the full set of ten complex nucleon-nucleon amplitudes at energies up to 800 MeV, as well as to continue investigating the possibility of the existence of dibaryon resonances. The given complex isospin-one amplitudes were fairly well determined, partly as a result of this work. The work in this period has involved measurements and analysis of data on elastic scattering and total cross sections for polarized neutrons on polarized protons. The pion-nucleus research continues the studies of this interaction in regions where it was not well explored. One set of experiments includes studies of pion elastic and double-charge-exchange scattering at energies between 300 and 550 MeV, where the data is unique. Another involves elastic and single-charge-exchange scattering of pions from polarized nuclear targets, a new field of research which will give the first extensive set of information on spin-dependent pion-nucleus amplitudes. Still another involves the first set of detailed studies of the kinematic correlations among particles emitted following pion absorption in nuclei. DOE N91-12329# Amsterdam Univ. (Netherlands). Melis vanderHorst, Jr. 1990 109 p Submitted for publication (ETN-90-97748) Avail: NTIS HC/MF A06 As an extension of a discussion of the production of standard model Higgs bosons at the HERA collider and the possibilities of producing charged Higgs bosons at HERA are discussed. Both Henricus Wilhelmus L Naus 1990 147 P Submitted for publication Sponsored by Stichting voor Fundamenteel Onderzoek der Materie, and Netherlands Organization for the Advancement of Pure Research (ETN-90-97749) Avail: NTIS HC/MF A07 The electromagnetic properties of off-shell nucleons are studied. Gauge invariance provides an important constraint. The electromagnetic interaction of a many body system is described, a Lagrangian formulation is used to illustrate the connections with analagous problems discussed, and the nonrelativistic Ward-Takahashi identities are derived. The general formalism of the off-shell electromagnetic vertex of a Dirac particle is presented. Off-shell effects in electron-nucleus scattering is addressed. The description of electromagnetic two step reactions involving hadrons when the internal structure of the hadrons is taken into account is discussed. General vertex operators are used, only constrained by Lorentz and gauge invariance. The electromagnetic production of pions on a nucleon is discussed as an example. ESA N91-12331# Helsinki Univ. of Technology, Espoo (Finland). Lab. of Physics. INTERACTION OF THE POSITRON AND THE POSITRONIUM ATOM WITH INSULATING FLUIDS AND SOLIDS Ph.D. Thesis Maarit Tuomisaari Finnish Academy of Technology 1990 36 P (Ph-165; ISBN-951-666-300-1; ISSN-0355-2721; ETN-90-97975) Avail: NTIS HC/MF A03 Experimental positron lifetime results in argon and xenon indicate, and theoretical calculations confirm, the clustering of atoms around the positron and the bubble formation around the positronium atom in a certain temperature and density range. The results may be generalized to practically all gases at temperatures not too far from the critical temperature. Positronium time of flight measurement on solid rare gases and several alkali halides indicate that energetically narrow positronium distributions are formed in the interior of wind band gap insulators. The energy distributions are well described by the Ore formation model. The energetic positronium formed at the positron implant depth diffuses to the surface, losing energy in the process. An analysis of the data using hot-carrier diffusion model simulations yields an estimate of the strength of the positronium-phonon coupling. The coupling is found to be energy dependent. ESA CALCULATION OF SPECTROSCOPIC PARAMETERS FOR DIATOMIC MOLECULES OF ATMOSPHERIC INTEREST Final Report, 2 Sep. 1987 31 Mar. 1990 R. H. Tipping Mar. 1990 19 p (Contract F19628-87-K-0055) (AD-A225251; GL-TR-90-0127) Avail: NTIS HC/MF A03 CSCL 20/8 A complete recalculation of fundamental spectroscopic parameters, in particular transitional frequency and line intensity, was accomplished for the diatomic molecules carbon monoxide (CO), and the hydrogen halides (HF, HCI, HBr, and HI). The results were cast into the form of the 1986 edition of the HITRAN molecular database. A primary goal of this effort was to produce parameters sufficient for the high temperature database, HITEMP, so that additional isotopic variants and additional hot and overtone bands for these species are included, also extending the bands to higher rotational levels than previously available. The spectral coverage is from the submillimeter region (pure rotational lines) through the visible (higher overtones). GRA N91-12333# Technische Univ., Delft (Netherlands). Mark Willem Konijnenberg 1990 106 p Sponsored by Netherlands Energy Research Foundation Measurements on the ratio between the contributions to the radiative neutron capture process by deuterons from states with total spin J = 1/2 and J = 3/2 are presented. It is shown that the outcome of these experiments can only be understood from the electromagnetic interactions with nucleons, mesons and nucleon resonances involving meson exchange. These mesons are the logical consequence of the fact that the strong nucleon-nucleon interaction potential is mediated by these particles. ESA 73 NUCLEAR AND HIGH-ENERGY PHYSICS Includes elementary and nuclear particles; and reactor theory. For space radiation see 93 Space Radiation. N91-12334# Air Force Systems Command, Wright-Patterson AFB, OH. Foreign Technology Div. THERMOIONIC CONVERTER FOR SPACE REACTOR Shengquan Cao and Jicai Yang 4 May 1990 14 p Transl. into ENGLISH from He Ke Xue Yu Gong Cheng (Peoples Republic of China), v. 4, no. 3, Sep. 1984 p 227-232 (AD-A225299; FTD-ID(RS)T-0385-90) Avail: NTIS HC/MF A03 CSCL 10/2 Thermionic converters offer many advantages for use as space reactors. Over the last several years, six experiments were performed, of which four were in-pile experiments and two out-pile experiments. Of the four in-pile experiments, three involved the use of three converters linked in series. The use of nuclear reactors as the power source for an electrical system in space is one of the important developmental projects under consideration today. For a time extending relatively long into the future, according to most opinions on potential power requirements, the choice of a thermionic converter to implement thermoelectric conversion has many advantages. GRA (NASA-CR-187368; NAS 1.26:187368) Avail: NTIS HC/MF_A07 CSCL 20F Scaling laws for light-weight optical systems are examined. A cubic relationship between mirror diameter and weight has been suggested and used by many designers of optical systems as the best description for all light-weight mirrors. A survey of existing light-weight systems in the open literature was made to clarify this issue. Fifty existing optical systems were surveyed with all varieties of light-weight mirrors including glass and beryllium structured mirrors, contoured mirrors, and very thin solid mirrors. |