Controlled Synthesis of Polyenes by Catalytic Methods. Progress Report for the period December 1, 1989 - November 30, 1992 (open access)

Controlled Synthesis of Polyenes by Catalytic Methods. Progress Report for the period December 1, 1989 - November 30, 1992

A more direct approach to polyenes by the direct polymerization of acetylenes has been achieved. We were able to show that polymerization of acetylene itself can be controlled with a well- characterized alkylidene catalyst, but only if a base such as quinuclidine is present in order to slow down the rate of propagation relative to initiation. (Quinuclidine may also stabilize vinylalkylidene intermediates formed in the reaction). Unfortunately, living polyenes'' were no more stable than isolated polyenes, and so this approach had its limitations. Direct polymerization of acetylene by Mo(CH-t-Bu)(NAr)(O-t-Bu){sub 2} was more successful, but inherent polyene instability was still a problem. The most important result of the past grant period is the finding that dipropargyl derivatives (HC=CCH{sub 2}XCH{sub 2}C=CH; X = CH{sub 2}, C(CO{sub 2}R){sub 2}, SiR{sub 2}, etc.), which have been reported to be cyclopolymerized by various classical catalysts by as yet unknown mechanisms, are polymerized by Mo(CH-t-Bu)(NAr)(OCMe(CF{sub 3}){sub 2}){sub 2} in dimethoxyethane. We speculate that intramolecular formation of a five-membered ring in the product of {alpha} addition is fast enough to yield another terminal alkylidene on the time scale of the polymerization reaction, while a six-membered ring is formed in a reaction involving a more reaction terminal alkylidene. …
Date: November 30, 1992
Creator: Schrock, R. R.
Object Type: Report
System: The UNT Digital Library
Stability of Resonator Configurations in the Presence of Free-Electron Laser Interactions (open access)

Stability of Resonator Configurations in the Presence of Free-Electron Laser Interactions

The stability of empty resonators (or cold cavities) has been widely studied, and is well understood. Here we consider the stability of symmetric resonator systems when there is a free-electron laser (FEL) interaction present within the cavity. We first construct a linear thick-lens model of the FEL and analytically study the dependence of resonator stability on its geometry. Next, we employ a nonlinear, three-dimensional FEL oscillator code to study the dependence of FEL performance on the cavity configuration. The analytic and numerical approaches are compared and it is shown that they agree quite well. It is found that the region of stability is shifted toward longer cavities, and beyond the concentric configuration. Between the confocal and the concentric configurations, where the empty-resonator analysis predicts stability, there now appear regions of instability. We find that operation near the concentric configuration is preferable, and operation very near the confocal should be avoided.
Date: November 1, 1992
Creator: Krishnagopal, S. & Sessler, Andrew M.
Object Type: Article
System: The UNT Digital Library
MARKAL-MACRO: An overview (open access)

MARKAL-MACRO: An overview

MARKAL-MACRO is an experiment in model linkage. This new tool is intended as an improvement over existing methods for energy policy assessment. It is designed specifically for estimating the costs and analyzing alternative technologies and policies proposed for reducing environmental risks such as global climate change or regional air pollution. The greenhouse gas debate illustrates the usefulness of linked energy-economy models. A central issue is the coupling between economic growth, the level of energy demands, and the evolution of an energy system to supply these demands. The debate is often connected with alternative modeling approaches. The competing philosophies may be labeled [open quotes]top-down macroeconomic[close quotes] and [open quotes]bottom-up engineering[close quotes] perspectives. Do macroeconomic models, with their descriptions of effects within the total economy but few technical details on the energy system, tend to overestimate future energy demands Conversely, do engineering models, ignoring feedbacks to the general economy and non-technical market factors but containing rich descriptions of technology options, tend to take too optimistic a view of conservation and the use of renewable energy sources Or is the principal difference that the engineering models ignore new sources of energy demands, and that the macroeconomic models ignore saturation effects for old categories …
Date: November 12, 1992
Creator: Hamilton, L.D.; Goldstein, G.A.; Lee, J.; Marcuse, W.; Morris, S.C. (Brookhaven National Lab., Upton, NY (United States)); Manne, A.S. (Stanford Univ., CA (United States)) et al.
Object Type: Report
System: The UNT Digital Library
China energy databook (open access)

China energy databook

The Energy Analysis Program (EAP) at the Lawrence Berkeley Laboratory (LBL) first becamc involved in Chinese energy issues through a joint China-US symposium on markets and demand for energy held in Nanjing in November of 1988. Discovering common interests, EAP began to collaborate on projects with the Energy Research Institute (ERI) of China's State Planning Commission. In the course of this work it became clear that a major issue in the furtherance of our research was the acquisition of reliable data. In addition to other, more focused activities-evaluating programs of energy conservation undertaken in China and the prospects for making Chinese industries more energy-efficient, preparing historical reviews of energy supply and demand in the People's Republic of China, sponsoring researchers from China to work with experts at LBL on such topics as energy efficiency standards for buildings, adaptation of US energy analysis software to Chinese conditions, and transportation issues-we decided to compile, assess, and organize Chinese energy data. We are hopeful that this volume will not only help us in our work, but help build a broader community of Chinese energy policy studies within the US.
Date: November 1, 1992
Creator: Sinton, J. E.; Levine, M. D.; Liu, Feng; Davis, W. B. (eds.) (Lawrence Berkeley Lab., CA (United States)); Zhenping, Jiang; Xing, Zhuang et al.
Object Type: Report
System: The UNT Digital Library
A modified direct preconditioner for indefinite symmetric Toeplitz systems (open access)

A modified direct preconditioner for indefinite symmetric Toeplitz systems

A modification is presented of the classical O(n[sup 2]) algorithm of Trench for the direct solution of Toeplitz systems of equations. The Trench algorithm can be guaranteed to be stable only for matrices that are (symmetric) positive definite; it is generally unstable otherwise. The modification permits extension of the algorithm to compute an approximate inverse in the indefinite symmetric case, for which the unmodified algorithm breaks down when principal submatrices are singular. As a preconditioner, this approximate inverse has an advantage that only matrix-vector multiplications are required for the solution of a linear system, without forward and backward solves. The approximate inverse so obtained can be sufficiently accurate, moreover, that, when it is used as a preconditioner for the applications investigated, subsequent iteration may not even be necessary. Numerical results are given for several test matrices. The perturbation to the original matrix that defines the modification is related to a perturbation in a quantity generated in the Trench algorithm; the associated stability of the Trench algorithm is discussed.
Date: November 1, 1992
Creator: Concus, P. (Lawrence Berkeley Lab., CA (United States) California Univ., Berkeley, CA (United States). Dept. of Mathematics) & Saylor, P. (Illinois Univ., Urbana, IL (United States). Dept. of Computer Science)
Object Type: Report
System: The UNT Digital Library
Poster session: Fifth users meeting for the Advanced Photon Source (open access)

Poster session: Fifth users meeting for the Advanced Photon Source

The Advanced Photon Source (APS), which is currently under construction as a national user facility at Argonne National Laboratory is a third-generation synchrotron x-ray source, one of only three in the world. It is expected to produce x-rays that are 10,000 times brighter than any currently produced elsewhere for use in research in a wide range of scientific areas. Users from industry, national laboratories, universities, and business will be able to come to the APS to conduct research either as members of Collaborative Access Teams (CATS) or as Independent Investigators. Principal users will be members of CATS, which will be building and operating all of the beamlines present in the first phase of APS beamline development. The first set of CATs has been selected through a competitive proposal process involving peer scientific review, thorough technical evaluation, and significant management oversight by the APS. This document is a compilation of posters presented at the Fifth Users Meeting for the Advanced Photon Source, held at Argonne National Laboratory on October 14--15, 1992. All CATs whose scientific cases were approved by the APS Proposal Evaluation Board are included. In addition, this document contains a poster from the Center for Synchrotron Radiation and Research …
Date: November 1, 1992
Creator: unknown
Object Type: Article
System: The UNT Digital Library
RF cavity development for the PEP-II B factory (open access)

RF cavity development for the PEP-II B factory

This paper describes the development of an RF cavity design for the proposed PEP-II asymmetric B factory. The high luminosity required of PEP-II provides challenges in the design of the RF cavities, most notably in the reduced higher-order mode (HOM) impedances that must be attained and in the power that must be dissipated in the cavity walls. This paper outlines the goals set in these regards, describes how the cavity has been developed to meet them, and presents the results of measurements on a low-power test model built to verify the HOM damping scheme.
Date: November 1, 1992
Creator: Rimmer, R.A.
Object Type: Article
System: The UNT Digital Library
Two dimensional NMR and NMR relaxation studies of coal structure (open access)

Two dimensional NMR and NMR relaxation studies of coal structure

This report covers the progress made on the title project for the project period. Four major areas of inquiry are being pursued. Advanced solid state NMR methods are being developed to assay the distribution of the various important functional groups that determine the reactivity of coals. Special attention is being paid to methods that are compatible with the very high magic angle sample spinning rates needed for operation at the high magnetic field strengths available today. Polarization inversion methods utilizing the difference in heat capacities of small groups of spins are particularly promising. Methods combining proton-proton spin diffusion with [sup 13]C CPMAS readout are being developed to determine the connectivity of functional groups in coals in a high sensitivity relay type of experiment. Additional work is aimed at delineating the role of methyl group rotation in the proton NMR relaxation behavior of coals.
Date: November 25, 1992
Creator: Zilm, K.W.
Object Type: Report
System: The UNT Digital Library
Laser field assisted photoemission using femtosecond laser pulses (open access)

Laser field assisted photoemission using femtosecond laser pulses

Photoemission from Cu mirror at a laser fluence of 10[sup 11] W/cm[sup 2], 300 fs, pulse is investigated for various angles of incidence, intensities and polarizations. Electron emission is enhanced by [approximately] 20 from s to p polarization and by 4 on changing the angle of incidence from 0 to 73 degree.
Date: November 1, 1992
Creator: Srinivasan-Rao, T.; Fischer, J. & Tsang, T.
Object Type: Article
System: The UNT Digital Library
Sanitary Landfill groundwater monitoring report, third quarter 1992 (open access)

Sanitary Landfill groundwater monitoring report, third quarter 1992

This report contains analytical data for samples taken during third quarter 1992 from wells of the LFW series located at the Sanitary Landfill at the Savannah River Site. The data are submitted in reference to the Sanitary Landfill Operating Permit (DWP-087A).
Date: November 1, 1992
Creator: Thompson, C.Y.
Object Type: Report
System: The UNT Digital Library
A test of the flavor independence of [alpha][sub s] at the Z[sup 0] resonance (open access)

A test of the flavor independence of [alpha][sub s] at the Z[sup 0] resonance

We compare the ratio of the strong coupling [alpha][sub s] measured in Z[sup 0] [yields] b[bar b] events to that measured in Z[sup 0] [yields] q[bar q](q=u,d,s,c) in the SLD experiment at SLAC. Z[sup 0] [yields] b[bar b] events are identified with the aid of a precision silicon vertex detector by requiring that at least three charged tracks pass more than 3.0[sigma] from the Z[sup 0] decay vertex. This method has an estimated efficiency of 54% with a purity of 71%. Jets are identified and counted by clustering charged tracks according to the JADE algorithm. By comparing the 3-jet fraction in tagged events to that in all hadronic events, we extract a preliminary result of [alpha][sub s](b)/[alpha][sub s](udsc) = 1.18 [plus minus] 0.11(stat) [plus minus] 0.05(sys).
Date: November 1, 1992
Creator: Junk, T.R. (Stanford Univ., CA (United States). Dept. of Physics)
Object Type: Article
System: The UNT Digital Library
ANL-W 779 pond seepage test (open access)

ANL-W 779 pond seepage test

The ANL-W 779 sanitary wastewater treatment ponds are located on the Idaho National Engineering Laboratory (INEL), north of the Argonne National Laboratory -- West (ANL-W) site A seepage test was performed for two Argonne National Laboratory -- West (ANL-W) sanitary wastewater treatment ponds, Facility 779. Seepage rates were measured to determine if the ponds are a wastewater land application facility. The common industry standard for wastewater land application facilities is a field-measured seepage rate of one quarter inch per day or greater.
Date: November 1, 1992
Creator: Braun, D.R.
Object Type: Report
System: The UNT Digital Library
Electron-electron interactions in fast neutral-neutral collisions (open access)

Electron-electron interactions in fast neutral-neutral collisions

Differential electron emission is studied for 50--500 keV H[sup +] and H atom impact on helium. Using the first Born formulation, it is shown that projectile electron-target electron interactions are expected to dominate the differential cross sections for low energy target electron emission induced by fast neutral projectile impact on any target. Measurements of the 15[degrees] electron emission were made in order to investigate this prediction. For low impact energies, a constant ratio between the hydrogen atom and proton impact cross sections was found for emitted electron velocities less than half the projectile velocity, V[sub p] But as the collision energy increased, for electron velocities less than 0.25 V[sub p], the cross section ratio increased as the emitted electron velocity decreased. This is interpreted as a signature of projectile electron-target electron interactions becoming dominant for distant collisions between neutral particles.
Date: November 1, 1992
Creator: DuBois, R.D. & Manson, S.T.
Object Type: Article
System: The UNT Digital Library
Bimolecular reaction dynamics from photoelectron spectroscopy of negative ions (open access)

Bimolecular reaction dynamics from photoelectron spectroscopy of negative ions

The transition state region of a neutral bimolecular reaction may be experimentally investigated by photoelectron spectroscopy of an appropriate negative ion. The photoelectron spectrum provides information on the spectroscopy and dynamics of the short lived transition state and may be used to develop model potential energy surfaces that are semi-quantitative in this important region. The principles of bound [yields] bound negative ion photoelectron spectroscopy are illustrated by way of an example: a full analysis of the photoelectron bands of CN[sup [minus]], NCO[sup [minus]] and NCS[sup [minus]]. Transition state photoelectron spectra are presented for the following systems Br + HI, Cl + HI, F + HI, F + CH[sub 3]0H,F + C[sub 2]H[sub 5]OH,F + OH and F + H[sub 2]. A time dependent framework for the simulation and interpretation of the bound [yields] free transition state photoelectron spectra is subsequently developed and applied to the hydrogen transfer reactions Br + HI, F + OH [yields] O([sup 3]P, [sup 1]D) + HF and F + H[sub 2]. The theoretical approach for the simulations is a fully quantum-mechanical wave packet propagation on a collinear model reaction potential surface. The connection between the wavepacket time evolution and the photoelectron spectrum is given by …
Date: November 1, 1992
Creator: Bradforth, S.E.
Object Type: Report
System: The UNT Digital Library
Water use, productivity and interactions among desert plants (open access)

Water use, productivity and interactions among desert plants

Productivity, stability, and competitive interactions among ecosystem components within aridlands are key processes related directly to water in deserts. This project assumes that integrated aspects of plant metabolism provide insight into the structure and function of plant communities and ecosystems. While it is difficult to extrapolate from instantaneous physiological observations to higher scales, such as whole plant performance or to the interactions between plants as components of ecosystems, several key aspects of plant metabolism are scalable. Analyses of stable isotopic composition in plant tissues at natural abundance levels provide a useful tool that can provide insight into the consequences of physiological processes over temporal and spatial scales. Some plant processes continuously fractionate among light and heavy stable isotopic forms of an element; over time this results in integrated measures of plant metabolism. For example, carbon isotope fractionation during photosynthesis results in leaf carbon isotopic composition that is a measure of the set-point for photosynthetic metabolism and of water-use efficiency. Thus it provides information on the temporal scaling of a key physiological process.
Date: November 17, 1992
Creator: Ehleringer, J.R.
Object Type: Report
System: The UNT Digital Library
Report on the UNIX tupleviewer'' challenge (open access)

Report on the UNIX tupleviewer'' challenge

One result of the 1991 B Factory Workshop at SLAC was the definition of a software benchmark project: a user-friendly data browsing tool called a tupleviewer''. The tupleviewer is a program which interactively displays 1-D and 2-D graphical plots from data stored as n-tuples. A set of rules define the minimum requirements for the tupleviewer, but the choices for platform, programming language, window system, graphics package and GUI development system are left open. The purpose of this project is to provide an arena in which to compare these open choices, as well as to provide a training exercise. The results of these efforts, including the experiences of the developers and comparisons between the projects are reported. In particular, comparisons are reported between the various GUI tool kits used.
Date: November 1, 1992
Creator: Harris, F. A.; Johnson, A. S.; Hollinger, J.; Glanzman, T.; Kunz, P. F.; Pavel, T. et al.
Object Type: Article
System: The UNT Digital Library
Review of technical justification of assumptions and methods used by the Environmental Protection Agency for estimating risks avoided by implementing MCLs for radionuclides (open access)

Review of technical justification of assumptions and methods used by the Environmental Protection Agency for estimating risks avoided by implementing MCLs for radionuclides

The Environmental Protection Agency (EPA) has proposed regulations for allowable levels of radioactive material in drinking water (40 CFR Part 141, 56 FR 33050, July 18, 1991). This review examined the assumptions and methods used by EPA in calculating risks that would be avoided by implementing the proposed Maximum Contaminant Levels for uranium, radium, and radon. Proposed limits on gross alpha and beta-gamma emitters were not included in this review.
Date: November 1, 1992
Creator: Morris, S.C.; Rowe, M.D.; Holtzman, S. & Meinhold, A.F.
Object Type: Report
System: The UNT Digital Library
First measurement of the left-right cross section asymmetry in Z boson production at E[sub cm] = 91. 55 GeV (open access)

First measurement of the left-right cross section asymmetry in Z boson production at E[sub cm] = 91. 55 GeV

The left-right cross section asymmetry for Z boson production in e[sup +]e[sup -] annihilation (A[sub LR]) has been measured at E[sub cm] = 91.55 GeV with the SLD detector at the SLAC Linear Collider (SLC) using a longitudinally polarized electron beam. The electron polarization was continually monitored with a Compton scattering polarimeter, and was typically 22%. We have accumulated a sample of [approximately]10,200 Z events. We find that A[sup LR] = 0.100 [plus minus] 0.044 [plus minus] 0.003 where the first error is statistical and the second is systematic. From this measurement, we determine the weak mixing angle defined at the Z boson pole to be sin[sup 2][theta](lept/w) = 0.2378 [plus minus] 0.0056.
Date: November 1, 1992
Creator: Rowson, P.C. (Columbia Univ., New York, NY (United States). Dept. of Physics)
Object Type: Article
System: The UNT Digital Library
Surface Modification of Tribological Components in Transportation (open access)

Surface Modification of Tribological Components in Transportation

This paper reviews a number of programs funded through the Engineered Tribological Interfaces (ETI) Task area of the Tribology Program that utilize energetic beams of atoms to enhance the mechanical and microstructural properties of near-surface regions to improve the tribological performance of critical components. The processes used in these programs include techniques based on chemical vapor deposition, physical vapor deposition, and ion implantation. A common feature of these techniques is their ability to produce dense and adherent modified surfaces without need for subsequent grinding/polishing treatments. Another feature of these techniques is their ability to introduce a wide range of elements into near-surface regions.
Date: November 1, 1992
Creator: Fenske, G. R.
Object Type: Article
System: The UNT Digital Library
The D[O] upgrade silicon tracker (open access)

The D[O] upgrade silicon tracker

A large silicon strip tracking detector is planned for the upgrade of the D0 experiment at Fermilab. This detector is designed to gag secondary vertices, to measure the momenta of charged particles and to operate in the high rate environment of the upgraded Tevatron. Details of the detector design are presented here.
Date: November 1, 1992
Creator: Heinson, A.P.
Object Type: Article
System: The UNT Digital Library
In situ containment and stabilization of buried waste (open access)

In situ containment and stabilization of buried waste

The objective of the project was to develop, demonstrate and implement advanced grouting materials for the in-situ installation of impermeable, durable subsurface barriers and caps around waste sites and for the in-situ stabilization of contaminated soils. Specifically, the work was aimed at remediation of the Chemical Waste (CWL) and Mixed Waste Landfills (MWL) at Sandia National Laboratories (SNL) as part of the Mixed Waste Landfill Integrated Demonstration (MWLID). This report documents this project, which was conducted in two subtasks. These were (1) Capping and Barrier Grouts, and (2) In-situ Stabilization of Contaminated Soils. Subtask 1 examined materials and placement methods for in-situ containment of contaminated sites by subsurface barriers and surface caps. In Subtask 2 materials and techniques were evaluated for in-situ chemical stabilization of chromium in soil.
Date: November 1, 1992
Creator: Allan, M. L.; Kukacka, L. E. & Heiser, J. H.
Object Type: Report
System: The UNT Digital Library
Measurement of radiation dose using radiochromic film (open access)

Measurement of radiation dose using radiochromic film

We have irradiated samples of radiochromic film to doses between 0.005 and lMrad in a Co[sup 60] facility at ANL. The doses computed using the manufacturer's calibration curves for the absorption at 600 and 510 nm have been compared with the dose obtained from ion chamber measurements. Excellent agreement is obtained and high precision can be maintained by baseline measurement of the films prior to irradiation, appropriate choice of film and wavelength used.
Date: November 24, 1992
Creator: Jankowski, D. J. & Proudfoot, J.
Object Type: Report
System: The UNT Digital Library
Reconstruction of twist grain boundaries in gold (open access)

Reconstruction of twist grain boundaries in gold

The reconstruction of high-angle twist grain boundaries on the four densest atomic planes in gold are investigated using the recently developed method of grand-canonical simulated quenching. It is found that the grain boundaries on the two densest planes, (111) and (100), do not reconstruct, while those on the (110) and (113) planes do.
Date: November 1, 1992
Creator: Phillpot, S. R.
Object Type: Article
System: The UNT Digital Library
Effects of air oxidation on the dissolution rate of LWR spent fuel (open access)

Effects of air oxidation on the dissolution rate of LWR spent fuel

Dissolution rates for air-oxidized spent fuel were measured in flowthrough tests. Results from two types of specimens, separated grains and multigrain particles, both in oxidized (U[sub 4]O[sub 9+x]) and unoxidized (UO[sub 2]) conditions indicated only minor effects of oxidation on the surface-area-normalized rates. Similar results were obtained for unirradiated specimens in three different oxidation states (UO[sub 2], U[sub 3]O[sub 7], and U[sub 3]O[sub 8]). These observations have important practical implications for disposal of spent fuel in a geologic repository as well as implications regarding the oxidative dissolution mechanism of UO[sub 2] fuel.
Date: November 1, 1992
Creator: Gray, W. J.; Thomas, L. E. & Einziger, R. E.
Object Type: Article
System: The UNT Digital Library