Lapas attēli
PDF
ePub

appropriately chosen coordinate frame whose origin falls freely along with the gyroscope and whose spatial coordinate axes point in fixed directions.

Author

N89-27454# Lawrence Livermore National Lab., CA. A TEST OF NEWTON'S LAW OF GRAVITY USING THE BREN TOWER, NEVADA P. Kasameyer, J. Thomas, O. Fackler, M. Mugge, J. Kammeraad, M. Millett, B. Harris, and D. Felske 22 May 1989 16 p Presented at the 8th Moriond Workshop on Tests of Fundamental Laws in Physics, Savoie, France, 21-28 Jan. 1989 (Contracts W-7405-eng-48; DE-AC03-81ER-40050) (DE89-013262; UCRL-101001; CONF-890199-5) Avail: NTIS HC A03/MF A01

Gravity values were predicted on a tower by upward continuing an extensive set of surface data in order to test the 1/r squared dependence of Newton's Law of Universal Gravitation. Gravity was measured at 12 heights up to 454 m on a tower at the Nevada Test Site, and at 91 locations on the surface of the earth within 2.5 kilometers of the tower. These data were combined with 60,000 surface gravity measurements within 300 kilometers of the tower and were used to predict the gravitational field on the tower via a solution of Laplace's equation. A discrepancy between the observed gravity values and the prediction could suggest a breakdown of Newtonian Gravity, but none were observed. Preliminary results are consistent with the Newtonian hypothesis to within 93 + or - 95 microgals at the top of the tower, a result which conflicts with the previously reported 500 microgal non-Newtonian signal seen at 562 meters above the earth.

DOE

N89-27457# National Bureau of Standards, Boulder, CO.
Electromagnetic Technology Div.
GROUP INDEX AND TIME DELAY MEASUREMENTS OF A
STANDARD REFERENCE FIBER
B. L. Danielson and C. D. Whittenberg Jul. 1988 20 p Sponsored
by NWC
(PB89-189179; NBSIR-88/3091) Avail: NTIS HC A03/MF A01
CSCL 20C

Measurement techniques for establishing a standard reference fiber with well characterized group index and time or group delay are described. Evaluation of an interferometric method indicates that fiber group index can be determined with a total estimated uncertainty of about 0.03 percent in small samples. Group delay of the reference fiber was measured with an overall uncertainty less than 0.004 percent in a 7 km waveguide. The application of

standard reference fiber to calibration of the distance measurement accuracy of an optical time-domain reflectometer (OTDR) is discussed.

Author

a

[blocks in formation]

26 p

71 ACOUSTICS

Includes sound generation, transmission and attenuation.
For noise pollution see 45 Environmental Pollution.

N89-27455# California Univ., Berkeley. Lawrence Berkeley Lab.
Engineering Div.
CRYOGENIC TECHNIQUES FOR LARGE SUPERCONDUCTING
MAGNETS IN SPACE
Michael A. Green Dec. 1988

Presented at the Space Cryogenics Workshop, Frascati, Italy, 18 Jul. 1988 (Contract DE-AC03-76SF-00098) (DE89-013431; LBL-25735; CONF-8807123-2) Avail: NTIS HC A03/MF A01

A large superconducting magnet is proposed for use in a particle astrophysics experiment, ASTROMAG, which is to be mounted on the United States Space Station. This experiment will have a two-coil superconducting magnet with coils which are 1.3 to 1.7 meters in diameter. The two-coil magnet will have zero net magnetic dipole moment. The field 15 meters from the magnet will approach earth's field in low earth orbit. The issue of high TC superconductor will be discussed in the paper. The reasons for using conventional niobium-titanium superconductor cooled with superfluid helium will be presented. Since the purpose of the magnet is to do particle astrophysics, the superconducting coils must be located close to the charged particle detectors. The trade off between the particle physics possible and the cryogenic insulation around the coils is discussed. As a result, the ASTROMAG magnet coils will be operated outside of the superfluid helium storage tank. The fountain effect pumping system which will be used to cool the coil is described in the report. Two methods for extending the operating life of the superfluid helium dewar are discussed. These include: operation with a third shield cooled to 90 K with a sterling cycle cryocooler, and a hybrid cryogenic system where there are three hydrogen-cooled shields and cryostat support heat intercept points.

DOE

N89-27459# Wyle Labs., Inc., Arlington, VA.
ROUTEMAP MODEL FOR PREDICTING NOISE EXPOSURE
FROM AIRCRAFT OPERATIONS ON MILITARY TRAINING
ROUTES Final Report, Jan. - Sep. 1988
Michael J. Lucas and Kenneth J. Plotkin Sep. 1988 95 p
(Contract F33615-85-C-0534; AF Proj. 7231)
(AD-A203849; WR-88-15; AAMRL-TR-88-060) Avail: NTIS HC
A05/MF A01 CSCL 20/1

Low altitude, high speed training operations are routinely conducted along specially designated Military Training Routes (MTRS). The location of these routes is continually changed for a variety of reasons. Each new route requires an environmental assessment to determine the community noise impact. A computer program, ROUTEMAP, is described which calculates the noise level on the ground along an MTR corridor. Program ROUTEMAP is a menu-driven program that runs on any IBM PC or PC-compatible computer. ROUTEMAP requires MS DOS Version 2.0 or later, with at least one megabyte of available disk space, 640 K of random access memory, and an 8087/80287 math coprocessor. The model requires the Air Force planner to specify the nature of the flight activity for the segment of the route in question. The information needed for each aircraft type are the number of day and night operations during a month, and nominal values for the airspeed, engine power setting, and altitude. In addition, the user must input whether the activity is usually under visual or instrument flying rules and if there are single or multiple flight tracks within the route corridor. With this input data, the program computes the onset rate-adjusted monthly day-night average A-weighted sound level, L sub dnmr in dB for ground positions located within 13 miles of the route centerline. For comparison purposes, the program also computes the monthly average A-weighted noise exposure level without the penalty for

N89-27456*# National Aeronautics and Space Administration.
Goddard Space Flight Center, Greenbelt, MD.
GEODETIC PRECESSION OR DRAGGING OF INERTIAL
FRAMES
Neil Ashby (Colorado Univ., Boulder.) and Bahman Shahid-Saless
Aug. 1989 14 p
(NASA-TM-100744; Rept-89B00267; NAS 1.15:100744) Avail:
NTIS HC A03/MF A01 CSCL 20C

In General Relativity, the Principle of General Covariance allows one to describe phenomena by means of any convenient choice of coordinate system. Here, it is shown that the geodetic precession of a gyroscope orbiting a spherically symmetric, nonrotating mass can be recast as a Lense-Thirring frame-draggi effect, in an

high onset rates and without the penalty for operations during the night. The program also computes the probability of being highly annoyed as a function of the L sub dnmr values. This information, along with the noise-compatible land-use guides normally associated with planning around airbases, can be used to interpret the noise resulting from military training route operations. Author

differences in ultra-sonic pulse transmission times has been developed. The method uses multiple-echo signals obtained by injecting a pulsed, plane ultrasonic wave of the compressional mode into a sample with free, parallel surfaces. The ultrasonic transducer employed for this purpose acts as both transmitter and receiver. The received ultrasonic signals are subjected to two consecutive Fourier transformations to produce a cepstrum. The cepstral function derived from the multiple-echo signal exhibits characteristic maxima whose positions on the frequency abscissa, after calibration in units of time, represent multiples of the ultrasonic transmission time. Since minute variations of this time can be determined from a shift in the position of a cepstral maximum, the detection of very small changes or differences in sample thickness or ultrasonic propagation velocity becomes feasible.

GRA

N89-27460# National Oceanic and Atmospheric Administration,
Boulder, CO. Wave Propagation Lab.
EIGEN: A PROGRAM TO COMPUTE EIGENRAYS FROM
HARPA (HAMILTONIAN ACOUSTIC RAY-TRACING PROGRAM
FOR THE ATMOSPHERE)/HARPO (HAMILTONIAN ACOUSTIC
RAY-TRACING PROGRAM FOR THE OCEAN) RAYSETS
A. M. Weickmann, J. P. Riley, T. M. Georges, and R. M. Jones
Feb. 1989 97 p
(PB89-165781; NOAA-TM-ERL-WPL-160) Avail: NTIS HC
A05/MF A01 CSCL 20A

EIGEN is a FORTRAN computer program that processes the rayset (machine-readable) output of the HARPA and HARPO acoustic ray-tracing programs. It interpolates in elevation angle to find the eigenrays that connect the source and a specified receiver. It also creates plots of range vs. elevation angle and range vs. travel time.

GRA

N89-27464# Dayton Univ., OH. Research Inst. KC-135R RUMBLE INVESTIGATION Final Report, Oct. 1986 · Jan. 1988 Michael L. Drake and Dennis G. Davis 27 Feb. 1989 242 p (Contract F33615-85-C-5040) (AD-A207532; UDR-TR-88-04; AFWAL-TR-88-4260) Avail: NTIS HC A11/MF A01 CSCL 01/3

The KC-135R is a modified KC-135A which has had, among other things, the engines changed from the J-57 to the new F-108-CF-100 engines. Shortly after the KC-135R began SAC flight operations, a noise problem perceived as a rumbling sound in the cabin area was found in various aircraft; i.e., Rumble. The Air Force, the aircraft manufacturer and the engine manufacturer studied the problem briefly developing a better definition of the general problem. The forcing function was determined to be the F-108 engine; however, the precise source of the noise and vibration, and the transmission path from the engine to the cabin were unknown.

GRA

N89-27461 Department of the Air Force, Washington, DC.
MULTICHANNEL PHASE NOISE MEASUREMENT SYSTEM
Patent
Stephen P. Caldwell, inventor (to AF), James T. Haynes, inventor
(to AF), and S. Buchalter, inventor (to AF) 31 May 1988 6 p
Filed 21 Apr. 1986 Supersedes AD-D012372
(AD-D014056; US-Patent-4,748,399; US-Patent-Appl-SN-853827)
Avail: US Patent and Trademark Office CSCL 12/9

A multichannel phase noise measuring system is disclosed which is capable of measuring the phase noise of two signal source operating between 100 MHz and 24 GHz. This system has two input channels and a mixer which produces a difference frequency between the signals received in the input channels. The difference frequency containing the phase noise is frequency multiplied and amplified to raise the phase noise level 12 dB. The multiplied and amplified difference signal is phase locked to a commercially available frequency synthesizer with inferior noise characteristics to the units being tested. By amplifying the phase noise of the original signals above the phase noise levels of the commercially available frequency synthesizer, they become measurable.

GRA

29 p

N89-27462# Army Lab. Command, Fort Monmouth, NJ.
Electronics Technology and Devices Lab.
POLARIZATION MATRICES OF LITHIUM NIOBATE Technical
Report, Jan. 1988 - Jan. 1989
Arthur Ballato Apr. 1989
(AD-A207231; SLCET-TR-89-1) Avail: NTIS HC A03/MF A01
CSCL 09/1

In analytical treatments of piezoelectric-acoustic transducers, signal processors, and resonators, the electromechanical transduction mechanism is most often expressed in terms of the elements of the piezoelectric (e) or (d) matrices. Molecular interpretations of piezoelectricity, and especially electrooptical applications, usually involve polarization as the preferred variable, and consequently the alternative (a) and (b) matrices are of interest. The elements of these latter sets are calculated for lithium niobate from measured elastopiezodielectric constants taken from the literature.

GRA

N89-27465* # National Aeronautics and Space Administration.
Langley Research Center, Hampton, VA.
REDUCTION OF BLADE-VORTEX INTERACTION NOISE
USING HIGHER HARMONIC PITCH CONTROL
Thomas F. Brooks, Earl R. Booth, Jr., J. Ralph Jolly, Jr., William
T. Yeager, Jr., and Matthew L. Wilbur (Army Aviation Systems
Command, Hampton, VA.) Jul. 1989 20 p
(NASA-TM-101624; AVSCOM-TM-89-B-005; NAS 1.15:101624)
Avail: NTIS HC A03/MF A01 CSCL 20A

An acoustics test using an aeroelastically scaled rotor was conducted to examine the effectiveness of higher harmonic blade pitch control for the reduction of impulsive blade-vortex interaction (BVI) noise. A four-bladed, 110 in. diameter, articulated rotor model was tested in a heavy gas (Freon-12) medium in Langley's Transonic Dynamics Tunnel. Noise and vibration measurements were made for a range of matched flight conditions, where prescribed (open-loop) higher harmonic pitch was superimposed on the normal (baseline) collective and cyclic trim pitch. For the inflow-microphone noise measurements, advantage was taken of the reverberance in the hard walled tunnel by using a sound power determination approach. Initial findings from on-line data processing for three of the test microphones are reported for a 4/rev (4P) collective pitch control for a range of input amplitudes and phases. By comparing these results to corresponding baseline (no control) conditions, significant noise reductions (4 to 5 dB) were found for low-speed descent conditions, where helicopter BVI noise is most intense. For other rotor flight conditions, the overall noise was found to increase. All cases show increased vibration levels.

Author

N89-27463# Army Lab. Command, Watertown, MA. Material
Technology Lab.
CEPSTRAL METHOD FOR THE MEASUREMENT OF
ULTRASONIC PULSE TRANSMISSION TIME VARIATIONS
Final Report
Otto R. Gericke Apr. 1989 20 p
(AD-A207410; MTL-TR-89-25) Avail: NTIS HC A03/MF A01
CSCL 14/2

А. cise method for de ing relative nges or small

N89-27466*# United Technologies Research Center, East
Hartford, CT.
NOISE PRODUCED BY TURBULENT FLOW INTO A ROTOR:
THEORY MANUAL FOR ATMOSPHERIC TURBULENCE
PREDICTION AND MEAN FLOW AND TURBULENCE
CONTRACTION PREDICTION Final Report
J. C. Simonich Jun. 1989 23 p

(Contract NAS1-17763)
(NASA-CR-181789; NAS 1.26:181789) Avail: NTIS HC
A03/MF A01 CSCL 20A

Prediction of helicopter main rotor noise due to ingestion of atmospheric turbulence was analyzed. The analysis combines several different models that describe the fluid mechanics of the turbulence and the ingestion process. Two models, atmospheric turbulence, and mean flow and turbulence contraction were covered. The third model, covered in a separate report, describes the rotor acoustic mode. The method incorporates the atmospheric turbulence model and a rapid distortion turbulence contraction description to determine the statistics of the anisotropic turbulence at the rotor plane. The analytical basis for a module was provided which was incorporated in NASA'S ROTONET helicopter noise prediction program. The mean flow and turbulence statistics associated with the atmospheric boundary layer were modeled including effects of atmospheric stability length, wind speed, and altitude. The turbulence distortion process is modeled as a deformation of vortex filaments (which represent the turbulence field) by a mean flow field due to the rotor inflow.

Author

N89-27469*# Rensselaer Polytechnic Inst., Troy, NY. Dept. of Mathematical Sciences. LOW-FREQUENCY SOUND PROPAGATION MODELING OVER A LOCALLY-REACTING BOUNDARY USING THE PARABOLIC APPROXIMATION J. S. Robertson, W. L. Siegman, and M. J. Jacobson 31 Aug. 1989 26 p (Grant NAG1-929) (NASA-CR-185864; NAS 1.26:185864; RPI-Math-175) Avail: NTIS HC A03/MF A01 CSCL 20A

There is substantial interest in the analytical and numerical modeling of low-frequency, long-range atmospheric acoustic propagation. Ray-based models, because of frequency limitations, do not always give an adequate prediction of quantities such as sound pressure or intensity levels. However, the parabolic approximation method, widely used in ocean acoustics, and often more accurate than ray models for lower frequencies of interest, can be applied to acoustic propagation in the atmosphere. Modifications of an existing implicit finite-difference implementation for computing solutions to the parabolic approximation are discussed. A locally-reacting boundary is used together with a one-parameter impedance model. Intensity calculations are performed for a number of flow resistivity values in both quiescent and windy atmospheres. Variations in the value of this parameter are shown to have substantial effects on the spatial variation of the acoustic signal.

Author

32 p

72 ATOMIC AND MOLECULAR PHYSICS

Includes atomic structure, electron properties, and molecular spectra.

N89-27467* # National Aeronautics and Space Administration.
Langley Research Center, Hampton, VA.
NOISE RADIATION CHARACTERISTICS OF THE
WESTINGHOUSE WWG-0600 (600kW) WIND TURBINE
GENERATOR
Kevin P. Shepherd and Harvey H. Hubbard (Planning Research
Corp., Hampton, VA.) Jul. 1989

Sponsored by Solar
Energy Research Inst.
(NASA-TM-101576; NAS 1.15:101576) Avail: NTIS HC
A03/MF A01 CSCL 20A

Acoustic data are presented from five different WWG-0600 machines for the wind speed range 6.7 to 13.4 m/s, for a power output range of 51 to 600 kW and for upwind, downwind and crosswind locations. Both broadband and narrowband data are presented and are compared with calculations and with similar data from other machines. Predicted broadband spectra are in good agreement with measurements at high power and underestimate them at low power. Discrete frequency rotational noise components are present in all measurements and are believed due to terrain induced wind gradients. Predictions are in general agreement with measurements upwind and downwind but underestimate them in the crosswind direction.

Author

N89-27470# State Univ. of New York, Buffalo. Dept. of
Chemistry.
NONRESONANT INTERACTION OF A THREE-LEVEL ATOM
WITH CAVITY FIELDS. PART 4: ATOMIC DIPOLE MOMENT
AND SQUEEZING EFFECTS Technical Report
Xiao-shen Li, D. L. Lin, Thomas F. George, and Zhen-dong Liu
(Center of Theoretical Physics, Beijing, China ) Apr. 1989 43 p
Prepared in cooperation with Academia Sinica, Shanghai (Peoples
Republic of China); and Jiangxi Normal Univ., Nanchang (Peoples
Republic of China) Submitted for publication
(Contract N00014-86-K-0043)
(AD-A206788; UBUFFALO/DC/89/TR-97) Avail: NTIS HC
A03/MF A01 CSCL 20/5

The behavior of the dipole moment of a three-level atom interacting with cavity fields of arbitrary de-tunings is investigated. The time evolution and squeezing conditions of the components and correlation function of the dipole moment are calculated for three cases: One-mode field and Xi type-atom initially in the upper state, two-mode field and a Lambda-type atom initially in the upper state, and two-mode field and a Lambda-type atom initially in one of the lower states. A number of interesting features are found and discussed.

GRA

N89-27468* # United Technologies Research Center, East
Hartford, CT.
EXPERIMENTAL ASSESSMENT OF HELICOPTER ROTOR
TURBULENCE INGESTION NOISE IN HOVER Final Report
J. C. Simonich, R. H. Schlinker, and R. K. Amiet Jul. 1989

68 p

(Contract NAS1-17763)
(NASA-CR-181792; NAS 1.26:181792) Avail: NTIS HC
A04/MF A01 CSCL 20A

An experiment was conducted to assess the accuracy of a theory for non-isotropic turbulence ingestion. In order to generate non-isotropic turbulence in a controlled environment, a scale model rotor in a closed chamber was used so that the turbulence generated by the rotor was reingested by the recirculating flow. Simultaneous measurements of turbulence inflow properties and far field acoustics were acquired. Measurements confirmed that the inflow turbulence was highly non-isotropic. The measured aerodynamic properties were used as inputs for the noise prediction procedure. The general agreement between the non-isotropic noise prediction procedure and the experiment was good, although the procedure generally overpredicts the quasi-tonal low to mid range frequencies and underpredicts the higher broadband signals. The predicted sound power level as a function of polar angle was in close agreement with measurements, except near the rotor plane, which is not modeled by the present analysis. It is determined that the most sensitive parameter influencing the predicted noise was the turbulence intensity.

Author

N89-27471# North Texas State Univ., Denton. Dept. of Physics. TWO-PHOTON ABSORPTION CHARACTERIZATION OF HgCdTe Annual Interim Report, Aug. 1987 - Aug. 1988 David G. Seiler Jan. 1989 81 p (Contract DAAB07-87-C-F094; DA Proj. 1L1-61102-A-31-B) (AD-A207198) Avail: NTIS HC A05/MF A01 CSCL 20/3

Magneto-Optical measurements of Hg(1-x)Cd(X)Te alloys have provided a new means of studying impurities and defects in this important Il-VI material. Two-photon magnetoabsorption (TMPA) was used to accurately determine the temperature dependence of the energy gap of various HgCdTe alloys, revealing behavior that deviates from currently accepted models. In addition, magnetooptical techniques were used to detect the presence of both shallow and deep impurities/defects and accurately determine their activation energies, thus providing information necessary for understanding the electrical and optical properties of the material.

GRA

9 p

N89-27472# Los Alamos National Lab., NM. Theoretical Div.
FINAL STATE EFFECTS IN LIQUID He4: AN EXPERIMENTAL
TEST
P. E. Sokol, R. N. Silver, T. R. Sosnick, and W. M. Snow (Argonne
National Lab., IL.) 1989 Presented at the Workshop on
Momentum Distributions, Argonne, IL, 24 Oct. 1988
(Contract W-7405-eng-36)
(DE89-012615; LA-UR-89-1607; CONF-8810118-8) Avail: NTIS
HC A02/MF A01

Inelastic neutron scattering at high momentum transfers can provide direct information on the atomic momentum distribution n(p) when the Impulse Approximation (IA) is valid. In isotropic systems, the scattering in the IA is directly proportional to the longitudinal momentum distribution which is a function of a single scaling variable Y is identical with (M/Q)(omega - omega sub r), where M is the mass of the scatterer, Q is the momentum transfer, and omega sub r = Q squared/2M is the recoiled energy. However, the experimentally attainable Q's are not large enough to reach the IA limit. Deviations from the IA due to final state scattering by neighboring atoms, known as final state effects, will distort the observed scattering from the IA prediction. Thus, an understanding of deviations from the IA is essential to accurate determination of n(p). Liquid helium provides an excellent testing ground for studying FSE in a dense, strongly interacting system for two reasons. First, theoretical calculations of the momentum distributions are available in both the normal liquid, and superfluid phases. These calculations are believed to be quite accurate, since they agree well with several other measured properties of the liquid. In addition, n(p) in the superfluid exhibits a very sharp feature, the Bose condensate peak, which should be very sensitive to FSE. Comparison of the predicted scattering obtained from the theoretical n(p) using the IA to the experimentally observed scattering can be used to study deviations due to FSE

DOE

N89-27475# California Univ., Berkeley. Lawrence Berkeley Lab. Accelerator and Fusion Research Div. MULTIPLE-ELECTRON PROCESSES IN FAST ION-ATOM COLLISIONS A. S. Schlachter Mar. 1989 29 p Presented at the Workshop on Highly Charged lons: New Physics and Advanced Techniques, Berkeley, CA, 13-15 Mar. 1989 Submitted for publication (Contract DE-ACO3-76SF-00098) (DE89-012982; LBL-26900; CONF-890387-6) Avail: NTIS HC A03/MF A01

Research in atomic physics at the Lawrence Berkeley Laboratory Super-HILAC and Bevalac accelerators on multipleelectron processes in fast ion-atom collisions is described. Experiments have studied various aspects of the charge-transfer, ionization, and excitation processes. Examples of processes in which electron correlation plays a role are resonant transfer and excitation and Auger-electron emission. Processes in which electron behavior can generally be described as uncorrelated include ionization and charge transfer in high-energy ion-atom collisions. A variety of experiments and results for energies from 1 MeV/u to 420 MeV/u are presented.

DOE

N89-27476# Oak Ridge National Lab., TN. Engineering Physics and Mathematics Div. SHIELD OPTIMIZATION PROGRAM. PART 1: EXECUTIVE SUMMARY R. T. Santoro and T. A. Gabriel Jun. 1989 48 p (Contract DE-AC05-840R-21400) (DE89-013335; ORNL/TM-11143-Pt-1) Avail: NTIS HC A03/MF A01

Detailed studies have been completed to estimate the radiation-induced damage in sensitive electronic components carried on a space-based interceptor weapons platform. The architecture of the interceptor was devised to be as realistic as possible. The analyses were completed for natural (Van Allen belt protons and electrons at an orbital altitude of 500 km) and man-made (nuclear weapons: neutrons, gamma-rays, X-rays, and pumped electron belts) radiation expected to be encountered by a SDI platform. Studies have also been completed to determine the hydrodynamic responses of beryllium mirror surfaces to mono-energetic X-rays (1 and 2 keV). This work included the effects of impurities which are introduced into the surface during machining. Finally, a comparison of the HULL and PUFF-TFT codes are presented which includes the thermo-mechanical response of an Al slab to 5 keV black body radiation.

DOE

N89-27473# Illinois Inst. of Tech., Chicago. Dept. of Physics. THEORETICAL STUDIES IN ELEMENTARY PARTICLE PHYSICS Progress Report, Mar. 1988 - Jan. 1989 John Clements Collins 1989 20 p (Contract DE-FG02-85ER-40235) (DE89-012701; DOE/ER-40235/T5) Avail: NTIS HC A03/MF A01

This report briefly discusses the following topics: factorization, fundamental perturbative quantum chromodynamics (QCD); polarization and hard scattering; small x; Drell-Yan phenomenology; cosmic ray physics; cosmic strings and proton decay; dynamical symmetry breaking and inflation; and QCD as a model for

DOE

mesons.

N89-27474# Argonne National Lab., IL. Materials Science Div.
HIGH-TEMPERATURE BEHAVIOR OF GRAIN BOUNDARIES
FROM EMBEDDED ATOM METHOD MOLECULAR DYNAMICS
SIMULATION
J. F. Lutsko, D. Wolf, and S. R. Phillpot Dec. 1988 8 p
Presented at the Symposium on Atomic Scale Calculations in
Materials Science, Boston, MA, 28 Nov. - 3 Dec. 1988
(Contract W-31-109-eng-38)
(DE89-013641; CONF-8811147-3) Avail: NTIS HC A02/MF
A01

The behavior of a metallic grain boundary at high temperatures is studied using an embedded atom potential. A recently developed molecular dynamics code is used which allows the simulation of an isolated grain boundary at temperatures as high as the bulk melting point. The stability of the boundary below the melting point is studied and compared with earlier investigations which have suggested the existence of a premelting transition. It is found that the boundary migrates at high temperature but remains well defined up to the bulk melting point. In contrast to simulations of ideal crystals, it was not possible to superheat the grain boundary due to the nucleation of bulk melting at the boundary. DOE

N89-27477* # Old Dominion Univ., Norfolk, VA. Dept. of
Physics.
NUCLEAR FRAGMENTATION ENERGY AND MOMENTUM
TRANSFER DISTRIBUTIONS IN RELATIVISTIC HEAVY-ION
COLLISIONS Progress Report, period ended 30 Jun. 1989
Govind S. Khandelwal and Ferdous Khan Aug. 1989 152 p
(Contract NCC1-42)
(NASA-CR-185501; NAS 1.26:185501) Avail: NTIS HC
A08/MF A01 CSCL 20H

An optical model description of energy and momentum transfer in relativistic heavy-ion collisions, based upon composite particle multiple scattering theory, is presented. Transverse and longitudinal momentum transfers to the projectile are shown to arise from the real and absorptive part of the optical potential, respectively. Comparisons of fragment momentum distribution observables with experiments are made and trends outlined based on our knowledge of the underlying nucleon-nucleon interaction. Corrections to the above calculations are discussed. Finally, use of the model as a tool for estimating collision impact parameters is indicated.

Author

N89-27478# Los Alamos National Lab., NM.
PHYSICS WITH ETA MESONS
Lon-chang Liu 1989 16 p Presented at the Symposium on
Pion-nucleon and Nucleon-nucleon Physics, Leningrad, USSR, 22
Apr. 1989

(Contract W-7405-eng-36) (DE89-012582; LA-UR-89-1751; CONF-8904233-1) Avail: NTIS HC A03/MF A01

Since the advent of pion factories, an impressive amount of information about the nuclear dynamics of the delta (1232) pion-nucleon resonance has been obtained. The study of this isospin-3/2 resonance has greatly benefited from the fact that pi(-)n and pi(+) systems are pure l = 3/2 states, which couple only to the delta in the resonance region. Such isospin selectivity of the pion does not exist, however, for the l = 1/2 N* resonances because it is not possible to form a pure | 1/2 state with a pion and a nucleon. Eta mesons have zero isospin. Consequently, the (eta)N systems are in a pure 1 = 1/2 state, and eta can be used to tag those N* resonances to which it strongly couples. We will briefly review the N interaction from the threshold region to c.m. energy square root of s is approximate or to 1600 MeV. It is seen how improved (pi)N data can help the study of (eta)N interactions. What new information about the hadronic interaction that can be learned from the study of eta production in pp collisions is discussed. The behavior of eta meson in nuclei will be discussed. The interesting question of the quark structure of eta(549) and eta'(958) will also be discussed within the framework of a simple model.

DOE

illustrations (ISSN-0173-6256; ETN-89-94607) Copyright Avail: NTIS HC A08/MF A01

Theoretical studies are devoted to elementary particle physics, renormalization of quantum field theories, methods of statistical mechanics, investigation of standard models, supersymmetry, strings, membranes, elementary particles in cosmology, neutrino detectors, nonrelativistic particle physics and quantum history. Experimental studies concern the production and transformation processes of elementary particles neutrino-nucleon interactions, electron-proton storage ring HERA, electronic equipment for CERN, ALEPH project, NA32, DELOS, and HEGRA experiments. ESA

N89-27482# Rome Univ. (Italy). Dipartimento di Fisica.
SOME CONSIDERATIONS ON THE BIRTH OF MOLECULAR
PHYSICS IN THE FIRST HALF OF THE 19TH CENTURY
(ALCUNE CONSIDERAZIONI SULLA NASCITA DELLA FISICA
MOLECOLARE NELLA PRIMA META' DELL'OTTOCENTO)
M. Grilli and F. Sebastiani 30 Jun. 1988 21 p in ITALIAN
(Nota-Interna-917; ETN-89-94736) Avail: NTIS HC A03/MF
A01

The history of the introduction of molecular concepts in physics is discussed, including Mosotti's analysis of intramolecular forces (1836), dielectric polarization, and double refraction.

ESA

N89-27479# Lawrence Livermore National Lab., CA. Theoretical Atomic and Molecular Physics Group. MOLECULES IN INTENSE LASER FIELDS S. N. Dixit and V. Mckoy (California Inst. of Tech., Pasadena.) May 1989 5 p Presented at the NATO Advanced Study Institute on Atoms in Strong Fields, Kos, Greece, 9-21 Oct. 1988 Submitted for publication (Contract W-7405-eng-48) (DE89-013807; UCRL-101134; CONF-8810376-1) Avail: NTIS HC A02/MF A01

In this paper, we will present some thoughts on the dynamics of interaction of molecules with intense laser fields. We will discuss the possible role of dissociation and autoionization in influencing the overall resonant enhanced multiphoton ionization (REMPI) dynamics. Our arguments are of a speculative and qualitative nature and the hope is to stimulate the reader in the complex issues related to the intense field molecule interaction. It is hoped that carefully controlled experiments and new developments in theoretical techniques will help unravel the underlying details of the REMPI dynamics.

DOE

N89-27483# Rome Univ. (Italy). Dipartimento di Fisica.
PRECISION MEASUREMENTS WITHOUT POLARIZATION AT
LEP
E. Longo 4 Aug. 1988 18 p Presented at the Workshop on
Polarization, Geneva, Switzerland, 9-11 Nov. 1987 Submitted for
publication
(Nota-Interna-921; ETN-89-94740) Avail: NTIS HC A03/MF
A01

Many measurements, in particular precision tests of the Standard Model, will be based on energy scans, say a coarse one through the whole range of the machine, and a finer one across the resonance. An integrated luminosity of 50 p/b should safely lead to the limits set by the systematics. Similarly, 100 to 200 p/b on top of the Z(0) will fully probe the discovery potential of unpolarized LEP-1. These figures must be completely revised in the case of unexpected deviations from Standard Model predictions or (even more) in the case of new discoveries, for instance to the case where the top is in the LEP-1 range. Standard measurements at LEP-2 call for a substantially higher amount of integrated luminosity (order of 500 p/b), so that every effort should be invested in reaching for this phase the highest possible performances of the machine.

ESA

N89-27480 Max-Planck-Inst. fuer Plasmaphysik, Garching
(Germany, F.R.).
INFLUENCE OF PARTICLE COLLISIONS ON THE
CHARACTERISTICS OF H-LIKE ION EMISSION DUE TO
CHARGE EXCHANGE REACTIONS WITH FAST ATOMS
A. A. Korotkov Jan. 1989 41 p
(IPP-III/142; ETN-89-94574) Copyright Avail:
Fachinformationszentrum Karlsruhe, 7514
Eggenstein-Leopoldshafen 2, Fed. Republic of Germany

The effective emission cross-sections of CVI (3434 A, 5291 A, 7717 A), NVII (3887 A, 5669 A, 7926 A), OVIII (2976 A, 4341 A, 6068 A) lines in charge-exchange reactions of nuclei with hydrogen atoms are calculated. The ground state and the first excited state of hydrogen are considered. The calculation takes into account the mixing of nl-levels due to collisions with plasma deuterons and electrons and Stark 1-mixing in the Lorentz field (V bar X B bar). Calculation of the effective cross-sections with allowance for the atomic beam density distribution in the plasma allows the determination of the line intensities. The influence of the fine structure and Zeeman splitting on the 2976 A OVII line profile is considered.

ESA

N89-27484# Rome Univ. (Italy). Dipartimento di Fisica.
SEARCH FOR THE INCLUSIVE PRODUCTION OF J/psi IN
e(+)e(-) COLLISIONS USING PLUTO DATA
F. Ferrarotto 27 Oct. 1988 15 p
(Nota-Interna-923; ETN-89-94742) Avail: NTIS HC A03/MF
A01

Inclusive production of J/psi was searched for in e+ e- hadronic events collected by the PLUTO detector at the storage ring PETRA in a range of energies from 30 to 35 GeV. The data were analyzed identifying muons in multihadronic events and looking for the decay mode J/psi yields mu(+)mu(-). With no candidate found, the upper limit obtained for the total cross section is sigma (e+ e- yields J/psi + X) less than or 12 pb (90 percent C.L.) using an integrated luminosity (integral of dL approx. = 42 p/b) at the average c.m. energy, square root of s 34.4 GeV. Together with previous results, this rules out a model based on nonperturbative quantum chromodynamic (QCD) production mechanisms. ESA

N89-27481# Max-Planck-Inst. fuer Physik und Astrophysik, Munich (Germany, F.R.). Inst. fuer Physik. (ACTIVITIES OF THE WERNER-HEISENBERG INSTITUTE OF PHYSICS] Annual Report, 1988 (JAHRESBERICHT 1988) Dec. 1988

In GERMAN Original contains color

N89-27485# Rome Univ. (Italy). Dipartimento di Fisica.
FIRST RESULTS FOR THE DELTA I = 1/2 AMPLITUDE IN K
DECAYS, WITH QUENCHED LATTICE QCD AND WILSON
FERMIONS
M. B. Gavela, L. Maiani, S. Petrarca, G. Martinelli, and O. Pene
(Centre National de la Recherche Scientifique, Orsay, France )

157 p

« iepriekšējāTurpināt »