The author have studied by means of numerical simulations the dynamical evolution of a network of cosmic strings, both in the radiation and matter era. Our basic conclusion is that a scaling solution exists, i.e., the string energy density evolves as t/sup -2/. This means that the process by which long strings dump their energy into closed loops (which can gravitationally radiate away) is efficient enough to prevent the string domination over other forms of energy. This conclusion does not depend on the initial string energy density, nor on the various numerical parameters. On the other hand, the generated spectrum of loop sizes does depend on the value of our numerical lower cutoff (i.e., the minimum length of loop we allow to be chopped off the network). Furthermore, the network evolution is very different from what was assumed before), namely the creation of a few horizon sized loops per horizon volume and per hubble time, which subsequently fragment into about 10 smaller daughter loops. Rather, many tiny loops are directly cut from the network of infinite strings, and it appears that the only fundamental scale (the horizon) has been lost. This is probably because a fundamental ingredient had been overlooked, …

Recently revised estimates of target gain have added additional optimistic inputs to the interface between targets, accelerators and fusion chamber beam transport. But it remains valid that neutralization of the beams in the fusion chamber is useful if ion charge state Z > 1 or if > 1 kA per beamlet is to be propagated. Some engineering and economic considerations favor higher currents.

All the products now obtained from oil can be provided by thermal conversion of the solid fuels biomass and coal. As a feedstock, biomass has many advantages over coal and has the potential to supply up to 20% of US energy by the year 2000 and significant amounts of energy for other countries. However, it is imperative that in producing biomass for energy we practice careful land use. Combustion is the simplest method of producing heat from biomass, using either the traditional fixed-bed combustion on a grate or the fluidized-bed and suspended combustion techniques now being developed. Pyrolysis of biomass is a particularly attractive process if all three products - gas, wood tars, and charcoal - can be used. Gasification of biomass with air is perhaps the most flexible and best-developed process for conversion of biomass to fuel today, yielding a low energy gas that can be burned in existing gas/oil boilers or in engines. Oxygen gasification yields a gas with higher energy content that can be used in pipelines or to fire turbines. In addition, this gas can be used for producing methanol, ammonia, or gasoline by indirect liquefaction. Fast pyrolysis of biomass produces a gas rich in ethylene …

The design of future Engineering Test Reactor (ETR) to demonstrate ignition is complicated by the uncertainties in the projected database for ignited plasmas. Application of uncertainty analysis to ETR design utilizing a figure-of-merit defined as the probability of ignition is presented. Performance evaluation from the uncertainty analysis in density-temperature space can locate an optimum operating window for ignition. 11 refs., 5 figs., 3 tabs.

A number of novel features of QCD are reviewed, including the consequences of formation zone and color transparency phenomena in hadronic collisions, the use of automatic scale setting for perturbative predictions, null-zone phenomena as a fundamental test of gauge theory, and the relationship of intrinsic heavy colored particle Fock state components to new particle production. We conclude with a review of the applications of QCD to nuclear multiquark systems. 74 references.

There is an observable and definable process that occurs during the course of responding to an abnormal event at a nuclear power plant. Each of the elements that comprise that process involves collective action and consequently is influenced by the character and effectiveness of organizational and managerial arrangements. Factors which affect each element include overt ones like the allocation of authority and responsibility and the skill of personnel, as well as covert factors like the methods used to resolve uncertainty. The purpose of this research project is to examine the process of response that occurs to an abnormal event at a nuclear power plant and where possible to identify the organizational and management factors that influence that process.

Hydrogen-bonding characteristics of molecules are extremely important in determining their boiling points, densities and water-solubilities, and these properties are important in understanding the adsorption of gases on charcoal. We show that empirical scales that measure hydrogen-bonding interactions can be correlated with the electrostatic properties of the molecules which agrees with previous worker's assessment that the hydrogen-bonding interaction is electrostatic in nature. Correlations both with single molecule properties as well as with the interaction energy between two molecules are found. This establishes a method for calculating these important properties which were previously available only through experiment or empirical scales. 12 refs., 3 figs.

One component of the neutron source associated with the decay of actinide nuclides in many environments is due to the interaction of decay /alpha/ particles in (/alpha/,n) reactions on low Z nuclides. Measurements of (/alpha/,n) thick target neutron yields and associated neutron spectra have been made for only a few combinations of /alpha/ energy and target nuclide or mixtures of actinide and target nuclides. Calculations of thick target neutron yields and spectra with the SOURCES code require /alpha/-energy-dependent cross sections for (/alpha/,n) reactions, as well as branching fractions leading to the energetically possible levels of the product nuclides. A library of these data has been accumulated for target nuclides of Z /le/ 15 using that available from measurements and from recent GNASH code calculations. SOURCES, assuming neutrons to be emitted isotopically in the center-of-mass system, uses libraries of /alpha/ stopping cross sections, (/alpha/,n) reaction cross reactions, product nuclide level branching fractions, and actinide decay /alpha/ spectra to calculate thick target (/alpha/,n) yields and neutron spectra for homogeneous combinations of nuclides. The code also calculates the thick target yield and angle intergrated neutron spectrum produced by /alpha/-particle beams on targets of homogeneous mixtures of nuclides. Illustrative calculated results are given and …

The potential of two photon processes to shed light on the parton content of resonances, we maintain, can only be realized in practice by moving towards an Amplitude Analysis of experimental data. By using the process ..gamma gamma.. ..-->.. ..pi pi.. as an example, the way to do this is discussed. Presently claimed uncertainties in the ..gamma gamma.. width of even the well-known f/sub 2/ (1270) are shown to be over-optimistic and the fitted couplings of the overlapping scalar states in the 1 GeV region meaningless. Only the use of Amplitude Analysis techniques on the new higher statistics data from SLAC and DESY can resolve these uncertainties and lead to definite and significant results. 37 refs., 18 figs.

The analog processing system for the Liquid Argon Calorimeter for the SLD project at SLAC is described. Amplification, storage of the analog information, and multiplexing is realized on specially developed hybrids, which will be mounted directly on the detector. This leads to a substantial reduction of the cable plant. Test results for the amplifier and for the sampling and multiplexing hybrid (CDU hybrid) are presented. The latter hybird contains a custom monolithic device, the Calorimeter Data Unit (CDU).

The Computer Documentation Group at Los Alamos National Laboratory plays an important role in the monthly change control process by documenting network component changes in a publication called the ICN Change Bulletin. BULLETIN is a menu-driven utility used by programmers and computer documentation writers to create articles for the ICN Change Bulletin, which is published in both hardcopy (printed) and softcopy (electronic) forms. BULLETIN also provides information used by other change control software tools. This paper describes the BULLETIN utility and its evolution from a single-purpose authoring tool to a complex, multipurpose authoring and change control tool. 4 refs., 4 figs.

Results are presented from the analysis of several final states from a high-sensitivity (4 ev/nb) study of inelastic K/sup -/p interactions at 11 GeV/c carried out in the LASS Spectrometer at SLAC. New information is reported on leading and underlying K* states, and the strangeonium states produced by hypercharge exchange exchange are compared and contrasted with those observed in radiative decays of the J/psi. 8 refs., 15 figs.

Sulfur and sulfur compounds have a wide range of applications for their fluid, electrical, chemical and biochemical properties. Although low in abundance on the Moon (/approximately/0.1% in mare soils), sulfur is surface-correlated and relatively extractable. Co-production of sulfur during oxygen extraction from ilmenite-rich soils could yield sulfur in masses up to 10% of the mass of oxygen produced. Sulfur deserves serious consideration as a lunar resource. 29 refs., 3 figs.

The wide ranging interest in the development of heavy ion synchrotrons with electron beam cooling is evident from the number of projects presently under way. Although much of the initial motivation for these rings stemmed from nuclear and particle physics, a considerable amount of atomic physics experimentation is planned. This paper surveys some of the new opportunities in atomic physics which may be made available with storage ring systems. 25 refs., 3 tabs.

The effect of coupling between horizontal and vertical betatron oscillations on the growth of a beam due to a intrabeam scattering has been studied. It was suggested that the presence of coupling may reduce the effects of intrabeam scattering. A procedure is outlined for revising intrabeam scattering theory to include coupling. There is one case where a plausible solution is not difficult to find, and this is the case of complete coupling. In this case, although coupling reduces the initial horizontal growth rate by a factor of 2, the final size of the beam after many hours is reduced by about 15%. An invariant is found that relates the energy spread and the transverse beam size that is valid at high energies and for the case of complete coupling.

The parameter B/sub e//nr/sub p/ (here, B/sub e/ is applied magnetic field strength, nr/sub p/ is the plasma density-radius product) is proposed as a key parameter for spheromak heating studies. If B/sub e//nr/sub p/ is too large, increased magnetic fluctuations limit heating; low B/sub e//nr/sub p/ value results in excessive radiation losses. An optimum range appears to be B/sub e//nr/sub p/ approx. 1 to 5 x 10/sup -20/ Wb.

One of the threats of concern to facilities using significant quantities of radioactive material is radiological sabotage. Both the Department of Energy (DOE) and the US Nuclear Regulatory Commission have issued guidance to facilities for radiological sabotage protection. At those facilities where the inventories of radioactive materials change frequently, there is an operational need for a technically defensible method of determining whether or not the inventory of radioactive material at a given facility poses a potential radiological sabotage risk. In order to determine quickly whether a building is a potential radiological sabotage target, Lawrence Livermore National Laboratory (LLNL) has developed a radiological sabotage consequence index that provides a conservative estimate of the maximum potential off-site consequences of a radiological sabotage attempt involving the facility. This radiological sabotage consequence index can be used by safeguards and security staff to rapidly determine whether a change in building operations poses a potential radiological sabotage risk. In those cases where such a potential risk is identified, a more detailed radiological sabotage vulnerability analysis can be performed. 1 tab.

The SO/sub 8/ and SP/sub 6/ models assume that the low-lying collective states of heavy nuclei are dominated by collective pairs of fermions coupled to angular momentum j = 0/sup +/, 2/sup +/. These models are generalizations of the pairing model (SP/sub 2/) to include the quadrupole degree of freedom. The expectation value of the spin operator in the SO/sub 8/ and SP/sub 6/ models is studied. 2 refs., 1 tab. (DWL)

This note summarizes the result of a study carried out on the aging effects in low pressure wire multiwire proportional chambers operated with gas mixtures containing TMAE. The purpose of the study was to investigate the effects of radiation damage in low pressure wire chambers used as a part of a BaF/sub 2/-TMAE calorimeter operated at high rates for an extended period of time. 8 refs., 6 figs.

The main goal of the CERN heavy-ion experiments is the search for an indication that the predicted state of deconfined quarks and gluons, the quark-gluon plasma (QGP), has been produced. The quantity most crucial to the probability of QGP formation is the thermalized energy density attained during the heavy-ion reaction. The amount of energy radiated transverse to the beam direction is the experimental quantity which is believed to be a measure of the amount of energy deposition in the reaction, and hence to reflect the energy density attained. In this presentation we consider the systematics of transverse energy production at CERN SPS energies, and we use the results to make estimates, under various assumptions, of attained energy densities.

Conceptual design studies of a tokamak Engineering Test Facility (ETF) are being carried out as a joint laboratory-industry effort at the ETF Design Center at Oak Ridge National Laboratory (ORNL). Designs are being developed for two reactors, one with a bundle divertor and one with a poloidal divertor. These machines, which are designed for ignition and a burn time of 100 s, both have a major radius of 5.4 m, a plasma minor radius of 1.3 m, and a D-shaped plasma elongation of 1.6. The plasma chamber must be conditioned at 10/sup -7/ torr. During the 35-s dwell between burns, the chamber must be pumped down from 5 x 10/sup -3/ torr to 3 x 10/sup -5/ torr. In the design with the bundle divertor four pairs of compound cryopumps, each pump with a 2-m/sup 2/ cryosorption pumping surface, are installed to pump down the plasma chamber. In the design with the poloidal divertor the plasma chamber is evacuated with the ten pairs of compound cryopumps, each pump with a cryosorption pumping surface of 4.32 m/sup 2/, installed to handle the divertor load. In both cases the pumps are installed in pairs so that one set can be regenerated while …

Sequential hypothesis tests applied to nuclear safeguards accounting methods make the methods more sensitive to detecting diversion. The sequential tests also improve transient signal detection in safeguards radiation monitors. This paper describes three microprocessor control units with sequential probability-ratio tests for detecting transient increases in radiation intensity. The control units are designed for three specific applications: low-intensity monitoring with Poisson probability ratios, higher intensity gamma-ray monitoring where fixed counting intervals are shortened by sequential testing, and monitoring moving traffic where the sequential technique responds to variable-duration signals. The fixed-interval controller shortens a customary 50-s monitoring time to an average of 18 s, making the monitoring delay less bothersome. The controller for monitoring moving vehicles benefits from the sequential technique by maintaining more than half its sensitivity when the normal passage speed doubles.

Particle control with pump limiters and divertors has been successfully demonstrated in a number of present-day tokamaks. In a heliotron/stellarator configuration, plasma flows to the wall in distinct flux bundles, often called ''divertor stripes''. This complicated three-dimensional characteristic of the plasma edge presents a new challenge for active particle control systems such as pump limiters and divertors. The experiment described here has obtained data with an instrumented pump particle collector that is located in the ''natural'' magnetic divertor stripe of Heliotron-E. The particle collector consists of a moveable graphite assembly with single-sided particle collection and active pumping. By scanning the particle collector assembly through the plasma edge of Heliotron-E, the divertor stripe is observed to be about 2-3 cm (FWHM) in width, and pressure rises of 0.01-0.01 mTorr are observed in the particle collector pumping chamber. These measurements have demonstrated that particles leaving the bulk plasma via the divertor stripes can be collected and provide a basis for developing a divertor scheme for particle control in helical systems. Modelling of the Heliotron-E magnetic configuration at the plasma edge is used to determine the collection efficiency of the particle collector in the divertor stripes. The modeling is further extended to describe …

In response to the need of the Strategic Defense Initiative (SDI) and long range space exploration and extra-terrestrial basing by the National Air and Space Administration (NASA), concepts for nuclear power systems in the multi-megawatt levels are being designed and evaluated. The requirements for these power systems are being driven primarily by the need to minimize weight and maximize safety and reliability. This paper will discuss the present requirements for space based advanced power systems, technological issues associated with the development of these advanced nuclear power systems, and some of the concepts proposed for generating large amounts of power in space. 31 figs.