Martin Marietta to develop an automated analysis system to integrate and analyze Superconducting Super Collider detector designs was investigated. (4) The thermal models that were developed in support of the Small Intercontinental Ballistic Missile flight tests were described. (5) The technical management role of the Product Integrity Engineer assigned to the Zenith Star spacecraft's Beam Control and Transfer Subsystem was discussed. The relationships between the engineering, business, security and social concerns associated with the practice of engineering and the management of programs by a major defense contractor are explored. Dissert. Abstr. N91-10193# Worcester Polytechnic Inst., MA. TRANSIENT CHARACTERISTICS OF UNCONFINED FIRE PLUME-DRIVEN CEILING JETS Final Report, 1986-1989 V. Motevalli and C. H. Marks May 1990 328 p Prepared in cooperation with Maryland Univ., College Park Sponsored by National Inst. of Standards and Technology, Gaithersburg, MD (Grant NIST-NANB5H0551) (PB90-227976; NIST/GCR-90/574) Avail: NTIS HC/MF A15 CSCL 21B An extensive study of small-scale, unconfined, fire-induced ceiling jets was conducted under ceiling transient and steady state conditions. Detailed velocity and temperature measurements of the ceiling jet were made simultaneously using the cross-correlation velocimetry technique from the start of the fire until the ceiling reached steady state. Velocity and temperature profiles were obtained at several radial locations away from the plume impingement point. These measurements were made for transient and steady ceiling jet conditions in the case of the H=1.0 m. All the transient measurements in the H=0.5 m case were limited to temperature measurements. At steady state, however, both temperature and velocity measurements were obtained. GRA N91-10194*# National Aeronautics and Space Administration. (NASA-TM-103501; MTB-316-87; NAS 1.15:103501) Avail: NTIS HC/MF A03 CSCL 13B This test program was initiated because a need existed at the Kennedy Space Center (KSC) to have this information readily available to the engineer who must make the choice of which electrostatic safe floor to use in a specific application. The information, however, should be of value throughout both the government and private industry in the selection of a floor covering material. Included are the test results of 18 floor covering materials which by test evaluation at KSC are considered electrostatically safe. Tests were done and/or the data compiled in the following areas: electrostatics, flammability, hypergolic compatibility, outgassing, floor type, material thickness, and available colors. Each section contains the test method used to gather the data and the test results. Author Oak Ridge National Lab., TN. Mathematical N91-10195# Presented at the BETECH 1990, A recently proposed method for treating boundary corners is applied to a problem of practical interest, the simulation of an three-dimensional electrochemical plating process. At an edge point on the cathode surface there are two unknown flux (normal derivative) values, and the hypersingular integral equation for the boundary derivatives is employed to complete the linear system of equations. The additional complications arising in electroplating are the presence of singular solutions at a reentrant corner, nonlinear boundary conditions, and the close proximity of two different edges. Results for a realistic problem geometry are reported. DOE N91-10196# Societe Europeenne de Propulsion, Vernon The purpose of the work is to show how the activities concerning operation safety can be incorporated into the industries for reaching optimum quality. For constructing the operation safety, an accurate description of the basic requirements is needed. In a second step the means and the tools available in the industry have to be considered. It is shown that the operation safety is reliable when the utilization performances are included in the product quality control. ESA N91-10197# Rolls-Royce Ltd., Derby (England). (PNR-90763; ETN-90-97962) Copyright Avail: NTIS HC/MF Engineering design, one of the most powerful forces in producing a package which matches market need, is discussed. It is essentially a detailed planning process backed by analysis and demonstration. The need for innovation to achieve competitive edge and profitability is considered. Innovation contains risk which must be controlled before substantial investment is made. The high rate of change of technology gives rise to the need for good training and retraining. Benefits which offsets costs at the time of occurring that cost are reached. ESA (PB90-207820; NTIA-90-259) Avail: NTIS HC/MF A06 CSCL 17B The report presents a detailed assessment of the hydrologic and meteorological operations in the 162 to 174 MHz (Very High Frequency) and 406.1 to 420 MHz (Ultra High Frequency) bands. The operations are currently supported by hydrologic and quasi-hydrologic channel assignments in these bands. There is a current need to jointly support hydrologic and nonhydrologic operations representing important national programs, and to develop solutions that alleviate spectral congestion and promote efficient spectrum utilization. The report identifies current regulations and channel usage, and analyzes the hydrologic emission characteristics to assess their bandwidth requirements and conservation alternatives. The current hydrologic channeling plans are also analyzed, and narrowband channeling options are the with potential hydrologic service assessed, along reaccommodation in current or other bands. All potential relocation and channeling options are explained and compared to illustrate their impact, tradeoffs, and compromises. The results of the study can serve to improve the spectral efficiency of hydrologic operations while remaining cost effective, and to conserve spectrum that can be made available for additional uses. N91-10200 Princeton Univ., NJ. SIGNAL DETECTION IN NON-GAUSSIAN AND NON-WHITE NOISE Ph.D. Thesis Pamela Ann Nielsen 1990 186 p Avail: Univ. Microfilms Order No. DA9014546 GRA Emphasis is on the analysis and synthesis of different methods of detection when the noise distributions are not completely known. The work concentrates on noise sources whose distributions fail to satisfy some commonly held assumptions. In particular, the interest here is in non-stationary, non-Gaussian environments. Initially, statistical modeling of such a noise source is examined. It is later shown that even if a model appears to represent the empirical probability mass function well, if the model is used to design a detector, the resulting detector may not have a performance which is significantly better than the performance of a simpler structure. In particular, it is shown that if the data is highly correlated, incorporating the correlation into the structure of the detector may result in a substantial improvement in performance as compared to the performance of a detector which is derived using only the univariate characteristics. In addition, several different techniques for sub-optimal pre-whitening are discussed and their effect on the performance of a detector is examined. The performance of several non-parametric detectors is examined and they are compared for a wide range of acoustic environments. The effect on the performance is examined when the detector has available a noise reference channel. Finally, a new detector is proposed which is based on higher order moments. In particular, the detector is based on the bi-covariance function which is known to be identically zero for Gaussian noise. The asymptotic performance of the sensor outputs as compared to a linear detector is derived. Several sample bispectra are given, along with a detailed example for multivariate Gaussian noise. Dissert. Abstr. N91-10201*# Michigan Univ., Ann Arbor. Radiation Lab. M. A. Ricoy and John L. Volakis (Grant NAG2-541) 1990 178 p (NASA-CR-186976; NAS 1.26:186976; Rept-025921-14-T) NTIS HC/MF A09 CSCL 20N Avail: Because material junction are commonplace in structures whose radar cross section is of interest, it is essential that their scattering properties be adequately characterized. To extend simple scattering models of material junctions with thin and/or high loss slabs to more general slabs, Generalized Impedance Boundary Conditions (GIBCs) and Generalized Sheet Transition Conditions (GSTCs) are proposed. The problem of the plane wave diffraction COMMUNICATIONS AND RADAR is examined by an arbitrary symmetric two-dimensional junction, where GIBCS and GSTCS are employed to simulate the slabs. GIBCS and GSTCs are constructed for multilayer planar slabs of arbitrary thickness and the resulting GIBC/GSTC_reflection coefficients are compared with exact counterparts to evaluate the GIBCS/GSTCs. The plane wave diffraction by a multilayer material slab recessed in a perfectly conducting ground plane is formulated and solved via the generalized scattering matrix formulation in conjunction with the dual integral equation approach. Various scattering patterns are computed and validated with exact results where possible. The diffraction by a material discontinuity in a thick dielectric/ferrite slab is considered by modelling the constituent slabs with GSTCs. A non-unique solution in terms of unknown constants is obtained, and these constants are evaluated for the recessed slab geometry by comparison with the obtained solution. Several other simplified cases are also presented and Author discussed. N91-10202# Sandia National Labs., Albuquerque, NM. Electromagnetic Testing Div. STATISTICAL CHARACTERIZATION OF A MODE-STIRRED J. G. Kostas and B. Boverie Jun. 1990 60 p (DE90-014860; SAND-90-1680) Avail: NTIS HC/MF A04 This report describes a statistical model for field amplitudes within a mode-stirred chamber. The parameters of the probability density function for field amplitudes are estimated by means of maximum likelihood. The accuracy of these parameters is specified as a function of the amount of data used. An experimental investigation of the possibility of using an existing electromagnetic shield room as a mode-stirred chamber is described. The physical alterations of the chamber and the instrumentation are summarized. Descriptions of the test results are reported. The tests were conducted to determine: the unloaded and loaded Q of the chamber, descriptive statistics of the electromagnetic fields, correlation distances of the fields in frequency, tuner angle, and DOE spatial position, and the possibility of using frequency stirring as an alternative to mechanical stirring. N91-10203# Lab. California Univ., Berkeley. Lawrence Berkeley Mar. 1990 MODES OF ELLIPTICAL WAVEGUIDES: A CORRECTION (Contract DE-AC03-76SF-00098) (DE90-016647; LBL-28702) Avail: NTIS HC/MF A03 It is shown that the fields associated with the TM(sub 01) mode of an elliptical wave guide are qualitatively different from those which have appeared in the standard literature for the past fifty years, and that the original fields as plotted were also in qualitative disagreement with the analytic expressions which accompanied them. Nonetheless, the cutoff frequencies given for that mode, as well as for the five other modes described in those references, are exceedingly accurate (within roughly 1 percent) for elliptical eccentricities as large as 0.75; for eccentricities in DOE excess of 0.9, the inaccuracy increases to from 5 to nearly 50 percent, depending on the mode in question. SPACECRAFT HEALTH AUTOMATED REASONING PROTOTYPE (SHARP): THE FISCAL YEAR 1989 SHARP PORTABILITY EVALUATIONS TASK FOR NASA SOLAR SYSTEM EXPLORATION DIVISION'S VOYAGER PROJECT David J. Atkinson, Richard J. Doyle, Mark L. James, Tim Kaufman, 18 Aug. 1990 33 p and R. Gaius Martin (Contract NAS7-918) (NASA-CR-187338; JPL-Publ-90-20; NAS 1.26:187338) Avail: NTIS HC/MF A03 CSCL 17B A Spacecraft Health Automated Reasoning Prototype (SHARP) portability study is presented. Some specific progress is described on the portability studies, plans for technology transfer, and potential applications of SHARP and related artificial intelligence technology to telescience operations. The application of SHARP to Voyager telecommunications was a proof-of-capability demonstration of artificial intelligence as applied to the problem of real time monitoring functions in planetary mission operations. An overview of the design and functional description of the SHARP system is also presented as it was applied to Voyager. Author N91-10205# Institut Franco-Allemand de Recherches, Saint-Louis (France). NUMERICAL SIMULATION OF ELECTROMAGNETIC BOUCLES FILIFORMES] P. Raymond and A. Carriere 21 Feb. 1989 63 p In FRENCH (ISL-R-102/89-Pt-1; ETN-90-97568) Avail: NTIS HC/MF A04 The physical modeling and numerical simulation of an electromagnetic accelerator composed of n fixed, coaxial coils accelerating a mobile coil are studied. All coils are supposed to be thin coils. This helps dimensioning of the electromagnetic device, in order to carry out the inverse ignition of a hollow charge (an active coil and a projectile ring), and to assess the necessary elements for studying an electromagnetic accelerator composed of n stages. ESA 46 P PRINCIPLES OF LOCSTAR SYSTEM EXPERIMENTS (CNES-CT/DRT/TIT/TR-88/355; ETN-90-97807) Avail: NTIS The description of the LOCSTAR system experiments is provided. The aim of the work is to get results about the LOCSTAR spread spectrum return link (mobile towards station), and to test the equipment designed by CNES. The measurement system is described. The methods and program allowing discussion and exploitation of the measurements are included. ESA N91-10208*# National Aeronautics and Space Administration. Lewis Research Center, Cleveland, OH. EFFECT OF SURFACE DEPOSITS ON ELECTROMAGNETIC WAVES PROPAGATING IN UNIFORM DUCTS Kenneth J. Baumeister Oct. 1990 13 p Presented at the 4th Biennial IEEE Conference on Electromagnetic Field Computation, Toronto, Ontario, 22-24 Oct. 1990 (NASA-TM-103282; E-5737; NAS 1.15:103282) Avail: NTIS HC/MF A03 CSCL 20N A finite-element Galerkin formulation was used to study the effect of material surface deposits on the reflective characteristics of straight uniform ducts with PEC (perfectly electric conducting) walls. Over a wide frequency range, the effect of both single and multiple surface deposits on the duct reflection coefficient were examined. The power reflection coefficient was found to be significantly increased by the addition of deposits on the wall. Author N91-10209# Consiglio Nazionale delle Ricerche, Frascati (Italy). Ist. di Fisica dello Spazio Interplanetario. FAST ESTIMATION OF THE VARIANCE OF A NARROWBAND PROCESS 25 p P. Astone, P. Bonifazi, and G. V. Pallottino Apr. 1990 (IFSI-90-16; ETN-90-97798) Avail: NTIS HC/MF A03 Estimation of the variance of a narrowband stationary random process in the presence of wideband observation noise is discussed. Reduction of the measurement time required to obtain accurate estimates is the goal of the exercise. A solution, based on the Wiener-Kolmogoroff optimum filter is discussed. Two simple suboptimal techniques are proposed. Computational simulations and experimental results on the Brownian motion of a cryogenic gravitational wave detector with high Q value confirm the theoretical prediction that the variance of a narrowband process can be determined in a time smaller than the correlation time of the process. ESA N91-10210# Ecole Centrale de Lyon (France). METHOD FOR SIMULATING LARGE DIMENSION DEVICES (ECL-90-10; ETN-90-97820) Avail: NTIS HC/MF A08 The electromagnetic compatibility of on-board electrical and electronic devices submitted to electromagnetic perturbation sources is investigated. The sources from the inside or outside of the spacecraft are considered. The coupling mechanisms between the sources and the devices are illustrated. A model allowing the description of electromagnetic compatibility is proposed. The frequency range from a few Hertz up to megaHertz is considered. ESA CONTRIBUTION TO THE STUDY OF THE ELECTROMAGNETIC FIELD RADIATION CLOSE TO Bei Lu 1990 151 p In FRENCH (ECL-90-12; ETN-90-97821) Avail: NTIS HC/MF A08 The disturbances generated by power electronic circuits are investigated. The electric and the magnetic fields created by a 60 KVA power generator, using fast commutation semiconductor switches, are analyzed. The developed theoretical and experimental tools are described. The intensity and the configuration of the electric and magnetic fields are evaluated. The localization and modeling of the emitting sources is carried out. ESA N91-10339# Meteorological Satellite Center, Tokyo (Japan). OUTLINE OF THE GMS TELECOMMUNICATION SYSTEM Masaru Fujimaki and Nobuyuki Taki In its Meteorological Satellite Center Technical Note. Special Issue (1989). Summary of GMS System. 1: Telecommunication System Mar. 1989 In P 1-5 JAPANESE; ENGLISH summary (For primary document see N91-10338 01-42) Avail: NTIS HC/MF A08 N91-10340# Meteorological Satellite Center, Tokyo (Japan). N91-10212 Michigan Univ., Ann Arbor. Avail: Univ. Microfilms Order No. DA9014036 As the switching speed of digital integrated circuits (ICs) increases, detrimental effects such as signal crosstalk, propagation delay, attenuation, dispersion, and reflection become more important. At relatively low switching speeds, the signals have small bandwidth and thus quasi-static electromagnetic modeling methods are sufficient to analyze these effects. However, integrated circuits having high-speed, wide-bandwidth signals, where the signal wavelengths are comparable to the dimensions of the IC and package, must be analyzed with a full-wave electromagnetic field method. A three-dimensional variable-mesh transmission line matrix (TLM) method is developed for the full-wave time-domain simulation of the electromagnetic properties of ICs. This is made more computationally efficient by rewriting the TLM scattering matrices in the form of finite-differences, yielding the finite-difference transmission line matrix (FD-TLM) method. Models for lumped circuit components, such as resistors, capacitors, diodes, and GaAs metal-semiconductor field-effect transistors (MESFETs) are derived and incorporated into the FD-TLM method, allowing the three-dimensional full-wave electromagnetic field simulation of complete active ICs. Applications of the method are discussed. Dissert. Abstr. N91-10214# Joint Publications Research Service, Arlington, VA. JPRS REPORT: SCIENCE AND TECHNOLOGY. USSR: ELECTRONICS AND ELECTRICAL ENGINEERING V. N. Akhtyrskiy and N. Ye. Fadeeva 17 Jul. 1990 24 p (JPRS-UEE-90-006) Avail: NTIS HC/MF A03 A collection of abstracts of Soviet literature which deal in the fields of electronics and electrical engineering is presented. Areas of concentration include communication equipment, broadcasting, digital systems, rail transportation, and solid state devices. One particular abstract discusses infrared-system receiving devices and a description is presented for certain types of such systems for detection and recognition of objects based on their heat radiation. M.G. Abstracts of Soviet literature in various areas of electronics and electrical engineering are compiled. The subject area is broadcasting and consumer electronics. M.G. N91-10218# Sandia National Labs., Albuquerque, NM. Kurt O. Wessendorf 1990 8 p Presented at the 12th Annual Piezoelectric Devices Conference, Kansas City, KS, 25-27 Sep. 1990 (Contract DE-AC04-76DP-00789) (DE90-014566; SAND-90-1085C; CONF-9009220-1) Avail: NTIS HC/MF A02 When quartz controlled oscillators are required for use in applications demanding precision many factors will ultimately place limitations on the ability of the oscillator to remain at the desired frequency. These factors include temperature, resonator Q, pullability, radiation, output load variability, and the electronic components. This paper addresses the subject of frequency instability of oscillator circuits due to power supply voltage variations. In particular, the primary sources of this instability are described for a Pierce oscillator employing a bipolar transistor and design techniques are presented which minimize these frequency pulling effects. DOE = A backward-wave oscillator (BWO) experiment is being conducted using a slow-wave structure which consists of a non-sinusoidal corrugated-wall waveguide with period z sub 0 = 1.67 cm, r sub min 1.17 cm, r sub max = 1.97 cm, and length L = 15.03 cm (nine periods). An annular electron beam is injected with the following parameters: Phi sub cathode = 1 MV, 1 KA less than or = I sub beam less than or = 7 KA in 1 KA increments, r sub beam = 0.9 cm, and t sub pulse approx. 60 ns. The guiding axial magnetic field is varied from 0.6 T to 3.0 T in 0.4 T increments. The device is designed to operate at 8.0 GHz less than f less than 8.5 GHz in the lowest-order TM mode of the coupled beam-structure system. The experimental design and results are presented. In addition, the theoretical and modeling work is discussed. DOE N91-10220# Argonne National Lab., IL. OVERDISCHARGE PROTECTION IN HIGH-TEMPERATURE (DE90-015180; US-Patent-Appl-SN-384604; Overdischarge indication and protection is provided in a lithium alloy-metal sulfide, secondary electrochemical cell and batteries of such cells through use of a low lithium activity phase that ordinarily is not matched with positive electrode material. Low lithium activity phases such as Li(0.1)AI(0.9) and LIAISI in correspondence with positive electrode material cause a downward gradient in cell voltage as an indication of overdischarge prior to damage to the cell. Moreover, the low lithium activity phase contributes lithium into the electrolyte and provides a lithium shuttling current as overdischarge protection after all of the positive electrode material is discharged. DOE N91-10221*# National Aeronautics and Space Administration. AN ANALYSIS OF THE EFFECTS OF SECONDARY |