An introduction to the noncommutative differential calculus on quantum groups. The invariant group average is also discussed.

We have used a temperature programmed, gas evolution technique to compare H{sub 2}S from coal and from pyrite in the presence of minerals or polymers. Pyrite decomposition in coal with H{sub 2}S release can be observed directly only if carbonate minerals, particularly iron-containing carbonates, are absent. Two distinct chemical mechanisms are required to model conversion of pyrite in coal to H{sub 2}S and pyrrhotite. Initially a reaction at pyrite grain surfaces (shrinking core model) occurs that is controlled by the rate of iron movement toward crystallite centers and by hydrogen-donor availability. Tar evolution (as indicated by methane-plus-ethane) also requires H-donors. Organic free radicals compete so efficiently for this scarce commodity that the rate of pyrite decomposition slows. At a 10 K/min heating rate, the rate of H{sub 2}S release by the H-donor mechanism reaches a maximum at 700 K and then decreases. Unimolecular decomposition of coal pyrite to FeS and S{sub 2} then occurs sharply at 830 K. Coal pyrolysis products effectively capture S{sub 2}, and the rate of H{sub 2}S release matches that of sulfur release from pure pyrite in a vacuum (0.07 mg- S/cm{sup 2}/min at 773 K). The high temperature H{sub 2}S evolution peak from coal is …

This paper describes instrumentation designed for BGO scintillator-based calorimetry of particles covering a very wide range of energies (from less than 50 MeV to 50 GeV). The instrumentation was designed to have a measurement accuracy of 0.1% over as much of the energy range as possible so the energy resolution of BGO would be the limiting factor. Two 1.5-cm{sup 2} photodiodes were used per 2.5 cm {times} 2.5 cm {times} 25 cm BGO crystal. Both a charge-sensitive preamplifier and a pulse processor were developed specifically for the needs of the WA80 experiment. The preamplifier was designed for high detector capacitance (100 to 700 pF), low integral and differential non-linearity and low power consumption (200 mW). The pulse processor is a time-invariant shaping amplifier with integral peak-detect-and-hold and automatic gain selection circuits. The amplifier use quasi-triangular shaping with 4 {mu}s peaking time, and the hold circuit is gated with a fast first level trigger. The system has more than 20 bits of effective resolution when used with an external 12-bit ADC. Results from beam tests at CERN are presented. 6 refs., 5 figs., 1 tab.

Some experiments to measure strangeness matrix elements of the proton are proposed. Two of these suggestions are described in some detail, namely electro-production of phi mesons and the difference between neutrino and antineutrino scattering for isospin zero targets such as deuterium.

An architecture for on-wafer processing is proposed for central silicon-strip tracker systems as they are currently designed for high energy physics experiments at the SSC, and for heavy ion experiments at RHIC. The data compression achievable with on-wafer processing would make it possible to transmit all data generated to the outside of the detector system. A set of data which completely describes the state of the wafer for low occupancy events and which contains important statistical information for more complex events can be transmitted immediately. This information could be used in early trigger decisions. Additional data packages which complete the description of the state of the wafer vary in size and are sent through a second channel. By buffering this channel the required bandwidth can be kept far below the peak data rates which occur in rate but interesting events. 18 refs.

The multiple scattering theory (MST) method of Korringa, and of Kohn and Rostoker for determining the electronic structure of solids, originally developed in connection with potentials bounded by non-overlapping spheres (muffin-tin (MT) potentials), is generalized to the case of space-filling potential cells of arbitrary shape through the use of a variational formalism. This generalized version of MST retains the separability of structure and potential characteristic of the application of MST to MT potentials. However, in contrast to the MT case, different forms of MST exhibit different convergence rates for the energy and the wave function. Numerical results are presented which illustrate the differing convergence rates of the variational and nonvariational forms of MST for space-filling potentials.

Lithium aluminate is an attractive material (in terms of its chemical, mechanical and irradiation properties) for breeding tritium in fusion reactors; however, its tritium release characteristics are not as good as those of other candidate materials. To investigate whether tritium release from lithium aluminate can be improved, we have studied the tritium release from irradiated samples of pure lithium aluminate, lithium aluminate doped with Mg, and lithium aluminate with a surface deposit of platinum. The release was studied by the temperature programmed desorption (TPD) method. Both the platinum coating and magnesium doping were found to improve the tritium release characteristics, as determined by TPD. Tritium release shifted to states with lower activation energies for the altered materials.

The magnetic properties of EuAs{sub 3} have been investigated by X-ray magnetic scattering with synchrotron radiation. No magnetic scattering could be detected in EuAs{sub 3} when the energy of X-rays was far away from the L absorption edges. Strong enhancement of magnetic intensities have been observed at the L{sub II} and L{sub III} absorption edges whereas no magnetic intensities could be detected at the L{sub I} absorption edge. The resonance enhancement at the L{sub III} absorption edge is stronger by a factor of about three compared to that the L{sub II} absorption edge. The magnetic properties of EuAs{sub 3} determined previously by neutron scattering could be reproduced by resonance X-ray scattering.

The tunability and the polarization of synchrotron radiation open upon new possibilities for the study of magnetism. Studies on magnetic materials performed at the National Synchrotron Light Source are reviewed, and thy fall into four areas: structure, evolution of magnetic order, separation of L and S, and resonance effects. In the vicinity of atomic absorption edges, the Faraday effect, magnetic circular dichroism, and resonant magnetic scattering are all related resonance effects which measure the spin polarized density of states. The production and analysis of polarized beams are discussed in the context of the study of magnetism with synchrotron radiation.

Factorial cumulant moments are used to analyze pseudorapidity fluctuations in A-A interactions. Only the second cumulant moments are significantly non-zero for central event samples, which implies that the higher order scaled factorial moments for the central data provide little information in addition to that from the second moments. The slopes of the cumulant plots are found to be inversely proportional to {eta} density for a variety of beam/target/energy combinations. We also present results on 2-D scaled factorial moments and the 2-particle correlations for central S+Au interactions.

This paper reviews the literature on rare earth(III) and actinide(III) hydroxide thermodynamics, in particular the determination of their enthalpies of formation at 25{degree}C. The hydroxide unit-cell volumes, lanthanide/actinide ion sizes, and solid-solution stability trends have been correlated with a generalized acid-base strength model for oxides to estimate properties for heterogeneous equilibria that are relevant to nuclear waste modeling and to characterization of potential actinide environmental interactions. Enthalpies of formation and solubility-product constants of actinide(III) hydroxides are estimated.

A investigation was conducted to devise a method to sense the laser beam intensity profile of an industrial laser welding system. The research focuses on monitoring methods and assessing locations within the system where data can be taken which reveal the relationship between the laser beam intensity profile and the input system parameters of the laser beam welding process. Emphasis has been placed on the configuration of a distributed computing environment to acquire, analyze and display the results of the sensed beam profile. Conventional image processing techniques are demonstrated. It was found that a distributed computing environment was useful for processing the large volumes of data generated by this process characterization method, and the distributed computing environment provided the computing power required for computationally intensive analysis and display techniques. The mathematical techniques used to discriminate one data set from another and relate the results to processing conditions are discussed.

The chemistry of conversion coatings on aluminum containing chromate and non-toxic chromate replacements has been investigated using XANES. Chromate conversion coatings contain 20% 6-valent chromium which is gradually lost on immersion in a corrosive environment. The most promising alternative coatings are those based on phosphotungstate. The chemistry of these and coatings containing Mo, V, and Mn are discussed.

We explore the use of the 2.2-km PEP storage ring at SLAC to drive a 40-{Angstrom} free-electron laser in the self-amplified spontaneous emission configuration. Various combinations for electron-beam and undulator parameters, as well as special undulator designs, are discussed. Saturation and high peak, in-band, coherent power (460 MW) are possible with a 67-m, hybrid permanent-magnet undulator in a ring bypass. A 100-m, cusp-field undulator can achieve high average, in-band, coherent power (0.25 W) in the main ring. The existing, 25.6-m, Paladin undulator at LLNL, with the addition of optical-klystron dispersive sections, is considered for both peak and average power. 35 refs., 4 figs., 1 tab.

Because thermal neutrons are scattered both by nuclei and by unpaired electrons, they provide an ideal probe for studying the atomic and magnetic structures of fine-grained magnetic materials, including nanocrystalline solids, thin epitaxial layers, and colloidal suspensions of magnetic particles, known as ferrofluids. Diffraction, surface reflection, and small angle neutron scattering (SANS) are the techniques used. With the exception of surface reflection, these methods are described in this article. The combination of SANS with refractive-index matching and neutron polarisation analysis is particularly powerful because it allows the magnetic and atomic structures to be determined independently. This technique has been used to study both dilute and concentrated ferrofluid suspensions of relatively monodisperse cobalt particles, subjected to a series of applied magnetic fields. The size of the cobalt particle core and the surrounding surfactant layer were determined. The measured interparticle structure factor agrees well with a recent theory that allows correlations in binary mixtures of magnetic particles to be calculated in the case of complete magnetic alignment. When one of the species in such a binary mixture is a nonmagnetic, cyclindrical macromolecule, application of a magnetic field leads to some degree of alignment of the nonmagnetic species. This result has been demonstrated …

Gamma-ray bursts (GRBs) remain an enigmatic astrophysical phenomenon some 20 years after their discovery. One of their unique characteristics is their continuum spectra which tend to be deficient in soft X-rays. Most of the energy of continuum emission comes from photons with energy above 100 keV (Epstein 1986). Following the recent detection of double absorption features in GB870303 and GB880205, and the interpretation of these features as the fundamental and first harmonic cyclotron lines great interest has been aroused in the mechanism of continuum emission in a strong magnetic field. In this paper, we describe some basic results of the production of continuum emission via up-scattering of low energy photons by relativistic electrons in a magnetic field. The dominant process is the cyclotron resonant scattering which we refer to as the Cyclotron Up-Scattering Process. See Ho and Epstein (1989a) for discussions on the non-magnetic (Compton) up-scattering process. A more detailed discussion of this work is presented in a separate paper (Ho, Epstein and Fenimore 1991).

Recent advances in chemical vapor deposition (CVD) technology has made available thin, free-standing polycrystalline diamond foils that can be used as the window material on high heat load synchrotron x-ray beamlines. Diamond windows have many advantages that stem from the exceptionally attractive thermal, structural, and physical properties of diamond. Numerical simulations indicate that diamond windows can offer an attractive and at times the only alternative to beryllium windows for use on the third generation x-ray synchrotron radiation beamlines. Utilization, design, and fabrication aspects of diamond windows for high heat load x-ray beamlines are discussed, and analytical and numerical results are presented to provide a basis for the design and testing of such windows.

The syntheses and physical properties of {kappa}-(ET){sub 2}Cu[N(CN){sub 2}]X (X=Br and Cl) are summarized. The {kappa}-(ET){sub 2}Cu[N(CN){sub 2}]Br salt is the highest {Tc} radical-cation based ambient pressure organic superconductor ({Tc}=11.6 K), and the {kappa}-(ET){sub 2}Cu[N(CN){sub 2}]Cl salt becomes a superconductor at even higher {Tc} under 0.3 kbar hydrostatic pressure ({Tc}=12.8 K). The similarities and differences between {kappa}-(ET){sub 2}Cu[N(CN){sub 2}]Br and {kappa}-(ET){sub 2}Cu(NCS){sub 2} ({Tc}=10.4 K) are presented. The X-ray structures at 127 K reveal that the the S{hor_ellipsis}S contacts shorten between ET dimers in the former compound while the S{hor_ellipsis}S contacts shorten within dimers in the latter. The difference in their ESR linewidth behavior is also explained in terms of the structural differences. A semiconducting compound, (ET)Cu[N(CN){sub 2}]{sub 2}, isolated during {kappa}-(ET){sub 2}Cu[N(CN){sub 2}]Cl synthesis is also reported. The ESR measurements of the {kappa}-(ET){sub 2}Cu[N(CN){sub 2}]Cl salt indicate that the phase transition near 40 K is similar to the spin density wave transition in (TMTSF){sub 2}SbF{sub 6}. A new class of organic superconductors, {kappa}-(ET){sub 2}Cu{sub 2}(CN){sub 3} and {kappa}-(ET){sub 2}Cu{sub 2}(CN){sub 3}-{delta}Br{delta}, is reported with {Tc}`s of 2.8 K (1.5 kbar) and 2.6 K (1 kbar), respectively.

The design and implementation of a distributed real-time control system for a compact synchrotron will be discussed. Graphic generation of accelerator device control logic, CAMAC device interfaces and operator display screens is presented. Beam digitization techniques and results of beam position and profile measurements is presented. Methods for automation of routine operator procedures will be discussed. 5 refs.

Distributed parameter system can be flexibly turned into lumped parameter system. Multiple control objectives such as profile and power control requirements can be simultaneously modeled. Profile control is essential to control the sawteeth inversion radius and optimum power production. In this paper, a simple self-tuning control scheme is used to analyze the tokamak control behavior. The model uncertainties can be accommodated in self-tuning systems.

We examine the structure of the exotic neutron-rich nucleus {sup 11}Li with an emphasis on understanding the origin of the soft E1 resonance and the neuron halo. The similarities and differences between shell model and di-neutron cluster model descriptions of the system are displayed using the Hecht expansion techniques. We find that the ground state {sup 11}Li as described in large shell model calculations is well approximated by the di-neutron cluster state. In contrast to the ground state, the soft E1 model of {sup 11}Li appears to have a more complicated structure and the E1 strength of this resonance is very sensitive to cancellations between p{yields}s and p{yields}d contributions to the dipole matrix elements. 12 refs., 6 figs., 3 tabs.

A technique for preshaping large particles of reacted glass for ultramicrotomy is described. This technique preserves delicate surface layers and results in more sections per block extending deeper into the sample than other techniques.

A random network model has been utilized to analyze the problem of tritium percolation through porous Li ceramic breeders. Local transport in each pore channel is described by a set of convection-diffusion-reaction equations. Long range transport is described by a matrix technique. The heterogeneous structure of the porous medium is accounted for via Monte Carlo methods. The model was then applied to an analysis of the relative contribution of diffusion and convective flow to tritium transport in porous lithium ceramics. 15 refs., 4 figs.

This report discusses the following topics on the relativistic projection and boost of solitons: The center of mass problem; momentum eigenstates; variation after projection; and the nucleon as a composite. (LSP).