Newsletter of the Texas Bureau of Disease Control and Epidemiology discussing the news, activities, and events of the organization and other information related to health in Texas.

Newsletter of the Texas Bureau of Disease Control and Epidemiology discussing the news, activities, and events of the organization and other information related to health in Texas.

The unique properties of X rays offer many advantages over electrons and other charged particles for the microcharacterization of materials. X rays are more efficient in exciting characteristic X-ray fluorescence and produce higher fluorescent signals to backgrounds than obtained with electrons. Detectable limits for X rays are a few parts per billion and are 10/sup -3/ to 10/sup -5/ less than for electrons. Energy deposition in the sample by X rays is 10/sup -3/ to 10/sup -4/ less than for electrons for the same detectable concentration. High-brightness storage rings, especially in the 6 GeV class with undulators, will be approximately 10/sup 3/ brighter in the X-ray energy range from 5 keV to 35 keV than existing storage rings and provide for X-ray microprobes that are as bright as the most advanced electron probes. Such X-ray microprobes will produce unprecedented low levels of detection in diffraction, EXAFS, Auger, and photoelectron spectroscopies for both chemical characterization and elemental identification. These major improvements in microcharacterization capabilities will have wide-ranging ramifications not only in materials science but also in physics, chemistry, geochemistry, biology, and medicine.

Recent developments in six areas of tandem-mirror theory are explored. Specifically, FLR terms (including electric-field drift) have been added to our 3-D paraxial MHD equilibrium code. Our low-frequency MHD stability analysis with FLR, which previously included only m/sub theta/ = 1 rigid perturbations, has been extended to incorporate moderate m/sub theta/, rotational drive, finite-beta effects on wall stabilization, and the well-digging effect of energetic electrons by using three computational techniques. In addition, we have examined the microstability of relativistic electrons with a loss-cone distribution, emphasizing the whistler and cyclotron-maser instabilities. We have also studied techniques for controlling radial transport, including the floating of segmented end plates and the tuning of transition-region coils, and have quantified the residual transport in a tandem mirror with axisymmetric throttle coils. Earlier work on the effect of ECRH on potentials in thermal-barrier cells has been extended. The transition between the weak- and strong-heating regimes has been examined using Fokker-Planck and Monte Carlo codes; an analytic model for the potentials relative to the end wall has been developed. Finally, our investigation of drift-frequency pumping of thermal-barrier ions has demonstrated that pumping is optimized when the magnetic fluctuation is perpendicular to both the unperturbed field and the …

An analysis was performed of the three existing measurements of the thermal conductivity and thermal diffusivity of molten uranium dioxide. A transient heat transfer code (THTB) was used for this analysis. A much smaller range of values for thermal conductivity than originally reported was found: the original values ranged from 2.4 to 11 W . m/sup -1/ . K/sup -1/, with a mean of 7.3 W . m/sup -1/ . K/sup -1/, whereas the recalculated values ranged from 4.5 to 6.75 W . m/sup -1/ . K/sup -1/, with a mean of 5.6 W . m/sup -1/ . K/sup -1/.

Some TDHF applications are addressed that are somewhat subtler than just crashing nuclei together and looking at large chunks of nuclear material. I will also attempt to address some of the technical problems of doing TDHF and also point out some areas where work remains to be done. Topics include promptly emitted particles, large amplitude RPA, and exciting giant resonances in heavy ion collisions. 19 references. (WHK)

Time Dependent Hartree-Fock theory, TDHF, is the most sophisticated, microscopic approach to nuclear dynamics yet practiced. Although it is far from a description of nature it does allow us to examine multiply interactive many-body systems semi quantum mechanically and to visualize otherwise covert processes. Some of the properties of the TDHF equations are stated leaving the interested reader to one of several excellent review articles for the derivations. Some of the applications to the collision of heavy ions are briefly described. (WHK)

The Workshop Report integrates what was said at the Workshop on New Directions in Soft X-Ray Photoabsorption, which focused on the region from 100 eV to 10 keV. The report clarifies the current state of theory and experiment and identifies the opportunities which new theoretical methods and experimental facilities could be expected to provide. The understanding of photoabsorption (which requires experimental photoabsorption cross section data) is a key to understanding the properties and behavior of atoms, molecules and solids. The Workshop participants were forty-three physicists and quantum chemists, from twenty-four institutions in four countries, all interested in photoabsorption from different perspectives.

The proposed arrangement of accelerator structures, waveguide feeds and klystrons is shown. A 50 MW klystron at 20-3C will provide power for the high-field capture section immediately following the target. About 1 meter downstream of this section there will be a standard girder of four 3.05-meter SLAC constant gradient accelerator sections. These will be powered by a klystron at station 20-3D. Current thinking is that this will also be a 50 MW tube, but 35 MW might well be sufficient. Both stations will be SLEDded. The length of the rectangular waveguide feed to the capture section will be approximately 132 ft, and the attenuation will be about 0.97 db. The corresponding numbers for the feed to the standard girder are 153 ft and 1.07 db. In CN-268 dated 6/22/84: Positron Source: First 50 Nanoseconds, K. Moffeit shows that good positron acceptance requires very high accelerating fields (on the order of 70 MV/m) in the first meter following the target. Various ways of approaching this gradient in a 1-meter section have been examined.

Slower growth projections in the demand for electricity and advances in metal fuel technology have shifted some of the emphasis in fast reactor development in the US from large oxide cores to small cores and also renewed interest in metal fuel. Cores constrained by diameter and fuel burnup exhibit many similar neutronic performance characteristics. However, some parameters such as reactivity coefficients, for example, are very different. The physics parameters of the four cores studied suggest that metal fueled cores, although less developed than oxide cores, are more flexible in adapting to currently changing deployment scenarios.

A wide range of phenomena is observed in heavy-ion collisions, calling for a comprehensive theory based on fundamental principles of many-particle quantum mechanics. At low energies, the nuclear dynamics is controlled by the mean field, as we know from spectroscopic nuclear physics. We therefore expect the comprehensive theory of collisions to contain mean-field theory at low energies. The mean-field theory is the subject of the first lectures in this chapter. This theory can be studied quantum mechanically, in which form it is called TDHF (time-dependent Hartree-Fock), or classically, where the equation is called the Vlasov equation. 25 references, 14 figures.

During start-up of the CERN AA, many hours of machine experiments went into the study and optimization of antiproton yields. Those involved in the commissioning programme experienced the difficulty of tuning a new machine to accept a low-intensity full-aperture beam. The antiproton yield could only be obtained by integrating a slow Schottky scan of the beam on the injection orbit, normalized with respect to primary beam intensity by a charge transformer just in front of the production target. A precise yield measurement took about five minutes. At high yields this method permitted measurements to within a few percent. The slowness of the multi-parameter yield optimization, starting from low yields where the measurement errors were often as large as the gains to be made, cannot be over emphasized. In the Tevatron I Debuncher the antiproton yields should be substantially higher than at the AA and, given a Schottky pick-up of sufficient sensitivity, the situation looks more promising. At the AA we have resolved some of our difficulties by improving the charge transformer signal, speeding up the Schottky scan and adding instrumentation to use the signals from pions, muons and electrons injected along with the antiprotons. Low yields, e.g. at reduced aperture, …

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This paper presents an overview of the production and economic models, with specific discussion of input assumptions used to derive microalgae product costs for the state of the art, theoretical-best and for the 1994 attainability target. These product cost estimates form the basis for developing program cost goals for microalgae fuel technology.

A weekly publication, the Texas Register serves as the journal of state agency rulemaking for Texas. Information published in the Texas Register includes proposed, adopted, withdrawn and emergency rule actions, notices of state agency review of agency rules, governor's appointments, attorney general opinions, and miscellaneous documents such as requests for proposals. After adoption, these rulemaking actions are codified into the Texas Administrative Code.

A weekly publication, the Texas Register serves as the journal of state agency rulemaking for Texas. Information published in the Texas Register includes proposed, adopted, withdrawn and emergency rule actions, notices of state agency review of agency rules, governor's appointments, attorney general opinions, and miscellaneous documents such as requests for proposals. After adoption, these rulemaking actions are codified into the Texas Administrative Code.

A weekly publication, the Texas Register serves as the journal of state agency rulemaking for Texas. Information published in the Texas Register includes proposed, adopted, withdrawn and emergency rule actions, notices of state agency review of agency rules, governor's appointments, attorney general opinions, and miscellaneous documents such as requests for proposals. After adoption, these rulemaking actions are codified into the Texas Administrative Code.

A weekly publication, the Texas Register serves as the journal of state agency rulemaking for Texas. Information published in the Texas Register includes proposed, adopted, withdrawn and emergency rule actions, notices of state agency review of agency rules, governor's appointments, attorney general opinions, and miscellaneous documents such as requests for proposals. After adoption, these rulemaking actions are codified into the Texas Administrative Code.

A weekly publication, the Texas Register serves as the journal of state agency rulemaking for Texas. Information published in the Texas Register includes proposed, adopted, withdrawn and emergency rule actions, notices of state agency review of agency rules, governor's appointments, attorney general opinions, and miscellaneous documents such as requests for proposals. After adoption, these rulemaking actions are codified into the Texas Administrative Code.

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This report provides an overview of the international debt problem which has significantly disturbed the international economic environment of the 1980s. It describes the characteristics of the less developed country (LDC) debt and discusses the role of major participants in the debt crisis. The study shows how the role of the participants has evolved during the crisis. Lastly, some of the issues arising from the debt crisis are discussed.