The authors list two major remedies for issues associated with fragmentation. they are

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Group 7D-Physical Chemistry

Chromatographic fingerprinting of complex biological samples is an active research area with a large and growing literature. Multivariate statistical and pattern recognition techniques can be effective methods for the analysis of such complex data. However, the classification of complex samples on the basis of their chromatographic profiles is complicated by two factors: (1) contounding of the desired group information by experimental variables or other systematic variations, and (2) random or chance classification effects with linear discriminants. The authors will treat several current projects involving these effects and methods for dealing with the effects. Complex chromatographic data sets often contain information dependent on experimental variables as well as information which differentiates between classes. Previously, Monte Carlo simulation studies were carried out to assess the probability of chance classification for nonparametric and parametric linear discriminants. The level of expected chance classification as a function of the number of observations, the dimensionality, and the class membership distributions were examined. These simulation studies established limits on the approaches that can be taken with real data sets so that chance classifications are improbable.

"Gamma ray radiolysis, lon molecule interactions,
Chemical reaction mechanisms, lon fragmentation.
The products formed in the gamma-radiolysis and
pulse-radiolysis of gaseous cyclohexane have been in-
terpreted in terms of the ion fragmentation, ion-mole-
cule reaction, and ion recombination mechanisms. It is
shown that the fragmentation of the parent ion is partly
quenched at a pressure of 55 torr. Ethylene and 1,3.
butadiene are the major products resulting from elec-
tron neutralization of these ions. Fragmentation is
strongly reduced when the neutralization process in-
volves an atomic- or polyatomic-anion rather than an
electron. For instance, addition of CCl4 to cyclohexane
results in a sharp drop of the yield of 1,3-butadiene,
and a concurrent rise in the yield of 2-C4H8.

500,612 PB86-162211

PC A13/MF A01
National Bureau of Standards, Gaithersburg, MD.
Technical Activities 1985 - Center for Radiation Research, C. E. Kuyatt. Oct 85, 288p NBSIR-85/3232 See also PB85-164952. Keywords: *Research projects, Radiation chemistry, *Nuclear physics, *Plasma radiation, Nuclear radi- ation, Laboratory equipment, Sources, lonizing radi- ation, Atomizing.

The report summarizes research projects, measure-

ment method development, calibration and testing,
and data evaluation activities that were carried out
during Fiscal Year 1985 in the NBS Center for Radi-
ation Research. These activities fall in the areas of
atomic and plasma radiation, radiation physics, radio- metric physics, radiation sources and instrumentation, ionizing radiation, and nuclear physics.

500,614 PB85-229391

Not available NTIS National Bureau of Standards (NML), Boulder, CO. Quantum Physics Div.

JILA (Joint Institute for Laboratory Astrophysics)

Portable Absolute Gravity Apparatus. Final rept., J. E. Faller, Y. G. Guo, J. Gschwind, T. M. Niebauer, and R. L. Rinker. 1983, 12p Sponsored by Air Force Geophysics Lab., Hanscom AFB, MA.

Pub. in Proceedings of the International Union of Ge-

odesy and Geophysics General Assembly (18th), Hamburg, Germany, August 15-27, 1983, p87-97. Keywords: *Gravimeters, "Gravity, Portable equip- ment, Accuracy, Laser interferometry.

At the Joint Institute for Laboratory Astrophysics, the

authors have developed a new and highly portable ab-
solute gravity apparatus based on the principles of
free-fall laser interferometry. A primary concern over
the past several years has been the detection, under-
standing, and elimination of systematic errors. In the
Spring of 1982, the authors used the instrument to
carry out a survey at twelve sites in the United States.
The time required to carry out a measurement at each
location was typically one day. Over the next several
years, the intention is to see absolute gravity measure-
ments become both usable and used in the field. To
this end, and in the context of cooperative research
programs with a number of scientific institutes through-
out the world, the authors are building additional instru-
ments (incorporating further refinements) which are to
be used for geodetic, geophysical, geological, and tec-
tonic studies. With these new instruments, the authors
expect to improve (perhaps by a factor of two) on the
6-10 microgal accuracy of their present instrument. Today one can make absolute gravity measurements as accurately as -- possibly even more accurately than -- one can make relative measurements.

500,609 PB86-166808

(Order as PB86-166782, PC A04/MF A01) National Bureau of Standards, Gaithersburg, MD. Thermodynamics of Solution of SO2(9) in Water and of Aqueous Sultur Dioxide Solutions, A. N. Goldberg, and V. B. Parker. 19 Jun 85, 18p Included in Jnl. of Research of the National Bureau of Standards, V90 n5 p341-358 Sep-Oct 85. Keywords: *Thermodynamics, *Sulfur dioxide, *Solutions, Water, Gibbs free energy, Specific heat, Enthalpy, Entrapy, Chemical equilibrium, Heat measurement, Tables(Data), Oxidation. A consistent set of thermochemical property values at 298.15K is given for the known constitutents of aqueous sulfur dioxide. Also tabulated are values of the mean ionic activity coefficients, osmotic coefficients, partial pressure of SO2(g), and the relative apparent molar enthalpy as a function of concentration of SO2(aq) at 298.15K. The data analysis considered a wide variety of measurement techniques: calormetric enthalpies of solution and reaction, heat capacities, equilibrium constants, solubilities, and vapor pressure measurement, both partial and total, over aqueous solutions of SO2 for the temperature range 278 to 393K. All auxiliary data have been taken from the most recent set of CODATA values which were converted to a standard state pressure of one bar (0.1 MPa). Parameters are given which extend the predictions to temperatures up to 373K.

500,610 PB86-166832

(Order as PB86-166782, PC A04/MF A01) National Bureau of Standards, Gaithersburg, MD. Chemical Kinetics - Theory and Experiment. Oct 85, 2p Included in Jnl. of Research of the National Bureau of Standards, V90 n5 p389-390 Sep Oct 85. Keywords: *Reaction kinetics, "Meetings, Laboratories, Experimental design, Reviews, Chemical physics, Numerical solution. The purpose of the conference was to bring together investigators from a broad range of institutions and backgrounds to review progress and problems in theoretical and experimental kinetics.

500,615 EARTH SCIENCES PB86-102951

Not available NTIS National Bureau of Standards (NML), Boulder, CO. AND Quantum Physics Div

High Precision Gravity Measurements.

Final rept., OCEANOGRAPHY

1. Marson, and J. E. Faller. 1985, 15p
Pub. in Proceedings of the Conference on High Preci-
sion Geodetics Measurements, University of Bologna, Bologna, Italy, October 16-17, 1984, p314-328 1985.

Keywords: *Gravity, Geodesy, Measurement. 8D. Geochemistry

The measurement of the gravity acceleration is of in

terest in a broad area of physical sciences: metrology, 500,613

geophysics and geodesy. High precision gravity data PB85-203438

Not available NTIS

are required to study gravity variation with time, the National Bureau of Standards, Gaithersburg, MD.

motion of the Earth's core, and mass redistribution in Nuclear and Chemical Dating Techniques: Inter

the mantle and crust. In this paper, measurement techpreting the Environmental Record. Final rept.,

niques employed in high precision gravity devices are

discussed. L. A. Currie. 1982, 517p

Pub. in ACS (American Chemical Society) Symposium

Series 176, p1-516 1982.

500,616 PB86-123098

Not available NTIS Keywords: "Geochemistry, Archaeology, Age esti- mation, "Radiocarbon dating, *Chemical analysis,

National Bureau of Standards (NML), Boulder, CO. Physicochemical properties, Meteorites,

Time and Frequency Div. Trees(Plants), Ice formation, Sediments, Mass spec-

Position Location Using Sequential GPS (Global troscopy, Thermoluminescence, Isotope dating, Re

Positioning System) Measurements. prints, State of the art.

Final rept.,

M. Weiss. 1982, 4p This volume is based on a symposium which took Pub. in Proceedings of IEEE (Institute of Electrical and place at the March 1980 National ACS Meeting in Electronics Engineers) Plans 82 Position Location and Houston, Texas. The general objective of the Sympo- Navigation Symposium, Atlantic City, NJ., December sium was to review the latest developments and state- 6-9, 1982, p275-278. of-the-art of scientific (physicochemical) dating methods together with biogeochemical applications. In view Keywords: Position(Location), Time measurement, of that objective the contents of this volume focus on Global positioning system. advances in knowledge, testing of assumptions, and model validation which can be brought about through The paper reports the development of a program to the use of complementary or multi-technique ap- derive a first order correction to initial estimates of proaches--i.e., chemical vs nuclear chronometers, and local coordinates and local clock bias from GPS time dating with nuclides differing in decay characteristics using a single channel GPS receiver of the CIA code. and chemical behavior. Among the topics included are: The program measures sequentially the local minus advances in isotope mass spectrometry and low-level GPS time via four different satellites based on an initial counting, resonance ion spectroscopy, direct atom estimate of local coordinates. Then using these meascounting with nuclear accelerators, amino acid racemi- urements along with known locations of the satellites zation, thermoluminescence, and the extraction of iso- the first order corrections to the X, Y, and Z coorditopic and chemical records from meteorites, ice cores, nates and the local time bias from GPS time are obsediment cores, and tree rings.

7E. Radio and Radiation Chemistry

500,611 PB85-202141

Not available NTIS National Bureau of Standards, Gaithersburg, MD. Pulse-Radiolysis and Gamma-Ray-Radiolysis of Cyclohexane - Ion Recombination Mechanisms. Final rept., P. Ausloos, R. E. Rebbert, F. P. Schwarz, and S. G. Lias. 1983, 17p Pub. in Radiation Physics and Chemistry 21, n 1-2 p27- 43 1983. Keywords: *Cyclohexane, "Radiolysis, lons, Ethylene, Butadiene, Neutralization, Reprints, *Pulse radiolysis,