Alarm points for fixed oxygen monitors (open access)

Alarm points for fixed oxygen monitors

Oxygen concentration monitors were installed in a vault where numerous pipes carried inert cryogens and gases to the Mirror Fusion Test Facility (MFTF-B) experimental vessel at Lawrence Livermore National Laboratory (LLNL). The problems associated with oxygen-monitoring systems and the reasons why such monitors were installed were reviewed. As a result of this review, the MFTF-B monitors were set to sound an evacuation alarm when the oxygen concentration fell below 18%. We chose the 18% alarm criterion to minimize false alarms and to allow time for personnel to escape in an oxygen-deficient environment.
Date: May 1, 1987
Creator: Miller, G.C.
System: The UNT Digital Library
Assessment of radioisotope heaters for remote terrestrial applications (open access)

Assessment of radioisotope heaters for remote terrestrial applications

This paper examines the feasibility of using radioisotope byproducts for special heating applications at remote sites in Alaska and other cold regions. The investigation included assessment of candidate radioisotope materials for heater applications, identification of the most promising cold region applications, evaluation of key technical issues and implementation constraints, and development of conceptual heater designs for candidate applications. Strontium-90 (Sr-90) was selected as the most viable fuel for radioisotopic heaters used in terrestrial applications. Opportunities for the application of radioisotopic heaters were determined through site visits to representative Alaska installations. Candidate heater applications included water storage tanks, sludge digesters, sewage lagoons, water piping systems, well-head pumping stations, emergency shelters, and fuel storage tank deicers. Radioisotopic heaters for water storage tank freeze-up protection and for enhancement of biological waste treatment processes at remote sites were selected as the most promising applications.
Date: May 1, 1987
Creator: Uherka, K.L.
System: The UNT Digital Library
Blown-up orbifolds (open access)

Blown-up orbifolds

A method to repair - ''blow-up'' - the singularities of the Abelian (2,2) orbifolds to obtain the corresponding (2,2) Calabi-Yau manifolds is presented. This approach makes use of the fact that with each orbifold singularity there are associated massless scalar fields - blowing-up modes - whose potential is flat to all orders in the string perturbation theory. The zero vacuum expectation values (VEV's) of the blowing-up modes correspond to the orbifold limit, while nonzero VEV's yield the corresponding Calabi-Yau manifold. One can then calculate explicitly, for such Calabi-Yau manifolds, the mass spectrum, Yukawa couplings, and all the other parameters of the effective Lagrangian by inserting successively all the background blowing-up modes with nonzero vacuum expectation value into the corresponding orbifold amplitudes. The results are exact at the string tree-level; however, they are perturbative in the blowing-up procedure. Mass spectra and Yukawa couplings for the blown-up Z/sub 3/ and Z/sub 4/ orbifolds are explicitly calculated. In particular all the E/sub 6/ singlets except the ones associated with the moduli-space of the blown-up orbifolds receive the mass; while the 27's and anti 27's do not pair up.
Date: May 1, 1987
Creator: Cvetic, M.
System: The UNT Digital Library
Challenges of nuclear fusion (open access)

Challenges of nuclear fusion

After 30 years of research and development in many countries, the magnetic confinement fusion experiments finally seem to be getting close to the original first goal: the point of ''scientific break-even.'' Plans are being made for a generation of experiments and tests with actual controlled thermonuclear fusion conditions. Therefore, engineers and material scientists are hard at work to develop the required technology. In this paper the principal elements of a generic fusion reactor are described briefly to introduce the reader to the nature of the problems at hand. The main portion of the presentation summarizes the recent advances made in this field and discusses the major issues that still need to be addressed in regard to materials and technology for fusion power. Specific examples are the problems of the first wall and other components that come into direct contact with the plasma, where both lifetime and plasma contamination are matters of concern. Equally challenging are the demands on structural materials and on the magnetic-field coils, particularly in connection with the neutron-radiation environment of fusion reactors. Finally, the role of ceramics must be considered, both for insulators and for fuel breeding purposes. It is evident that we still have a formidable …
Date: May 1, 1987
Creator: Kunkel, W.B.
System: The UNT Digital Library
Cryogenic detection of particles: Development effort in the United States (open access)

Cryogenic detection of particles: Development effort in the United States

The development of cryogenic detectors of particles, with emphasis on large mass devices, has been reviewed. Most groups are still tooling up and exploring basic properties of sensors. The main discussion themes are summarized and some of the early experimental results are described.
Date: May 1, 1987
Creator: Sadoulet, B.
System: The UNT Digital Library
The design and performance of the parallel multiprocessor nuclear physics data acquisition system, DAPHNE (open access)

The design and performance of the parallel multiprocessor nuclear physics data acquisition system, DAPHNE

The ever increasing complexity of nuclear physics experiments places severe demands on computerized data acquisition systems. A natural evolution of these systems, taking advantages of the independent nature of ''events,'' is to use identical parallel microcomputers in a front end to simultaneously analyze separate events. Such a system has been developed at Argonne to serve the needs of the experimental program of ATLAS, a new superconducting heavy-ion accelerator and other on-going research. Using microcomputers based on the National Semiconductor 32016 microprocessor housed in a Multibus I cage, CPU power equivalent to several VAXs is obtained at a fraction of the cost of one VAX. The front end interfacs to a VAX 11/750 on which an extensive user friendly command language based on DCL resides. The whole system, known as DAPHNE, also provides the means to reply data using the same command language. Design concepts, data structures, performance, and experience to data are discussed.
Date: May 1, 1987
Creator: Welch, L.C.; Moog, T.H.; Daly, R.T. & Videbaek, F.
System: The UNT Digital Library
Development of the Be(d,n) neutron source for cross-section investigations in the few-MeV energy range (open access)

Development of the Be(d,n) neutron source for cross-section investigations in the few-MeV energy range

Bombardment of thick Be-metal targets with several-MeV deuterons produces continuum-neutron fields which offer considerable potential for the development and validation of neutron-reaction cross sections. A facility based on this concept has been installed at the Argonne National Laboratory FNG accelerator. A description is provided of this facility and of the research studies which have been initiated to exploit its capabilities. Some technical considerations in the utilization of accelerator-produced continuum-neutron fields for reaction cross-section investigations are discussed. Results from several recent neutron-spectrum and integral cross-section measurements are presented, and the implications are reviewed. 13 refs., 8 figs.
Date: May 1, 1987
Creator: Smith, D. L.; Meadows, J. W.; Guenther, P. T. & Greenwood, L. R.
System: The UNT Digital Library
Effect of Dy additions on microstructure and magnetic properties of Fe-Nd-B magnets (open access)

Effect of Dy additions on microstructure and magnetic properties of Fe-Nd-B magnets

It is shown that increasing additions of Dy causes the remanence B/sub r/ to decrease linearly. The intrinsic coercivity, iHc, increases sharply for small additions of Dy, but the increase is not proportional for higher Dy contents. The iHc increases almost linearly with the effective anisotropy field of the RE/sub 2/Fe/sub 14/B phase until the Dy content is about 10% of the total rare earth content. Above this concentration, there is strong deviation from linearity. Various types of possible concentration profiles of the substituted rare earth are suggested. It is also argued that preferential segregation of Dy to the interfaces could be beneficial in increasing the nucleation field. Morphologically there is no apparent effect of Dy on the microstructure. However, in the 5 atomic % Dy sample, Dy rich oxides were observed. It is shown through Energy Dispersive Xray Spectroscopy (EDXS) line profiling that Dy partitions preferentially into the RE/sub 2/Fe/sub 14/B phase in all the cases. No segregation of Dy to the interphase interfaces has been detected.
Date: May 1, 1987
Creator: Ramesh, R.; Thomas, G. & Ma, B.M.
System: The UNT Digital Library
Effects of Impurities on Domain Growth (open access)

Effects of Impurities on Domain Growth

In the present report, the effects of both static and diffusing impurities on domain growth kinetics are considered. In particular, the Monte Carlo simulations for nonconservative (Glauber) dynamics are employed to examine the effects of quenched impurities on domain growth in the Potts model with varying degeneracy Q (2 less than or equal to Q less than or equal to 48). The effects of diffusing impurities are examined within the framework of the Ising model (i.e., Potts model with Q = 2) as a function of impurity diffusivity. Finally, a theoretical analysis of the diffusing-impurity results is presented.
Date: May 1, 1987
Creator: Srolovitz, D. J.; Grest, G. S.; Hassold, G. N. & Eykholt, R.
System: The UNT Digital Library
Electrochemical cell and electrode designs for high-temperature/high-pressure kinetic measurements (open access)

Electrochemical cell and electrode designs for high-temperature/high-pressure kinetic measurements

Many corrosion processes of interest to the nuclear power industry occur in high-temperature/high-pressure aqueous systems. The investigation of the kinetics of the appropriate electrode reactions is a serious experimental challenge, partially because of the high temperatures and pressures and partially because many of these reactions are very rapid, requiring fast relaxation measurements. An electrochemical measuring system is described which is suitable for measurements of the kinetics of fast electrode reactions at temperatures extending to at least 300C and pressures to at least 10 MPa (100 atmospheres). The system includes solution preparation and handling equipment, the electrochemical cell, and several electrode designs. One of the new designs is a coaxial working electrode-counter electrode assembly; this electrode can be used with very fast-rising pulses, and it provides a well defined, repeatedly-polishable working surface. Low-impedance reference electrodes are also described, based on electrode concepts responding to the pH or the redox potential of the test solution. Additionally, a novel, long-life primary reference electrode design is reported, based on a modification of the external, pressure-balanced Ag/AgCl reference electrode.
Date: May 1, 1987
Creator: Nagy, Z. & Yonco, R.M.
System: The UNT Digital Library
The evaporative vector: Homogeneous systems (open access)

The evaporative vector: Homogeneous systems

Molecular beams of van der Waals molecules are the subject of much current research. Among the methods used to form these beams, three-sputtering, laser ablation, and the sonic nozzle expansion of neat gases - yield what are now recognized to be ''warm clusters.'' They contain enough internal energy to undergo a number of first-order processes, in particular that of evaporation. Because of this evaporation and its attendant cooling, the properties of such clusters are time-dependent. The states of matter which can be arrived at via an evaporative vector on a typical laboratory time-scale are discussed. Topics include the (1) temperatures, (2) metastability, (3) phase transitions, (4) kinetic energies of fragmentation, and (5) the expression of magical properties, all for evaporating homogeneous clusters.
Date: May 1, 1987
Creator: Klots, C.E.
System: The UNT Digital Library
Exotic damping ring lattices (open access)

Exotic damping ring lattices

This paper looks at, and compares three types of damping ring lattices: conventional, wiggler lattice with finite ..cap alpha.., wiggler lattice with ..cap alpha.. = 0, and observes the attainable equilibrium emittances for the three cases assuming a constraint on the attainable longitudinal impedance of 0.2 ohms. The emittance obtained are roughly in the ratio 4:2:1 for these cases.
Date: May 1, 1987
Creator: Palmer, Robert B.
System: The UNT Digital Library
Experimental results on heavy flavour hadro- and photo-production (open access)

Experimental results on heavy flavour hadro- and photo-production

Results from experiments on the production of beauty and charm with hadron and photon beams are reviewed. Beauty production experiments are beginning to obtain b anti b cross-sections with hadron beams. Hadroproduction of charm is a somewhat more mature field, although high statistics are still eagerly sought. The situation is most promising with charm photoproduction experiments where total cross-sections, p/sub T//sup 2/ and X/sub F/ distributions and other production characteristics are now known in considerable detail.
Date: May 1, 1987
Creator: Purohit, M. V.
System: The UNT Digital Library
Experimenting with Langevin Lattice QCD (open access)

Experimenting with Langevin Lattice QCD

We report on the status of our investigations of the effects of systematic errors upon the practical merits of Langevin updating in full lattice QCD. We formulate some rules for the safe use of this updating procedure and some observations on problems which may be common to all approximate fermion algorithms.
Date: May 1, 1987
Creator: Gavai, R.V.; Potvin, J. & Sanielevici, S.
System: The UNT Digital Library
FEA predictions of residual stress in stainless steel compared to neutron and x-ray diffraction measurements. [Finite element analysis] (open access)

FEA predictions of residual stress in stainless steel compared to neutron and x-ray diffraction measurements. [Finite element analysis]

Residual stresses in a body arise from nonuniform plastic deformation and continue to be an important consideration in the design and the fabrication of metal components. The finite element method offers a potentially powerful tool for predicting these stresses. However, it is important to first verify this method through careful analysis and experimentation. This paper describes experiments using neutron and x-ray diffraction to provide quantitative data to compare to finite element analysis predictions of deformation induced residual stress in a plane stress austenitic stainless steel ring. Good agreement was found between the experimental results and the numerical predictions. Effects of the formulation of the finite element model on the analysis, constitutive parameters and effects of machining damage in the experiments are addressed.
Date: May 1, 1987
Creator: Flower, E. C.; MacEwen, S. R. & Holden, T. M.
System: The UNT Digital Library
Fermilab Industrial Affiliates roundtable on research technology in the twenty-first century (open access)

Fermilab Industrial Affiliates roundtable on research technology in the twenty-first century

This collection of articles presents views on the future of physics research by leading experts in the field. Topics discussed include particle physics, the Superconducting Super Collider, and the development of new superconducting materials. The articles have been abstracted and indexed separately.
Date: May 1, 1987
Creator: Carrigan, R. A., Jr. & Fenner, R. B.
System: The UNT Digital Library
Gas-cooled reactor for space power systems (open access)

Gas-cooled reactor for space power systems

Reactor characteristics based on extensive development work on the 500-MWt reactor for the Pluto nuclear ramjet are described for space power systems useful in the range of 2 to 20 MWe for operating times of 1 y. The modest pressure drop through the prismatic ceramic core is supported at the outlet end by a ceramic dome which also serves as a neutron reflector. Three core materials are considered which are useful at temperatures up to about 2000 K. Most of the calculations are based on a beryllium oxide with uranium dioxide core. Reactor control is accomplished by use of a burnable poison, a variable-leakage reflector, and internal control rods. Reactivity swings of 20% are obtained with a dozen internal boron-10 rods for the size cores studied. Criticality calculations were performed using the ALICE Monte Carlo code. The inherent high-temperature capability of the reactor design removes the reactor as a limiting condition on system performance. The low fuel inventories required, particularly for beryllium oxide reactors, make space power systems based on gas-cooled near-thermal reactors a lesser safeguard risk than those based on fast reactors.
Date: May 1, 1987
Creator: Walter, C.E. & Pearson, J.S.
System: The UNT Digital Library
Generation mixing and CP-violation, standard and beyond (open access)

Generation mixing and CP-violation, standard and beyond

We discuss several issues related to the observed generation pattern of quarks and leptons. Among the main topics: Masses, angles and phases and possible relations among them, a possible fourth generation of quarks and leptons, new bounds on neutrino masses, comments on the recently observed mixing in the B - anti B system, CP-violation, and recent proposals for a b-quark ''factory''.
Date: May 1, 1987
Creator: Harari, H.
System: The UNT Digital Library
Geology of Platanares geothermal area, Copan, Honduras (open access)

Geology of Platanares geothermal area, Copan, Honduras

The Platanares, Copan (Honduras) geothermal area is located in a highly faulted terrain of Paleozoic(.) metamorphic rocks, Cretaceous clastic sedimentary rocks, and Tertiary volcanic rocks. All thermal manifestations are located along faults. The volcanic rocks are probably too old to represent the surface expression of an active crustal magma body. Thus, the thermal water is interpreted to be heated during deep circulation in a regime of elevated heat flow. The water chemistry suggests that the geothermal reservoir originates within the Cretaceous sedimentary sequence and that the reservoir temperature may be as high as 240/sup 0/ C. Two exploration coreholes penetrated the volcanic sequence and bottomed within Cretaceous redbeds. Well PLTG-1 is 650 m deep and flows at 3 Mw thermal from a 160/sup 0/ C permeable zone. Well PLTG-2 is 401 m deep and has a thermal gradient of 139/sup 0/ C/km. Exploration drilling is continuing, with a third corehole to be drilled in May, 1987.
Date: May 1, 1987
Creator: Heiken, G.; Duffield, W.; Wohletz, K.; Priest, S.; Ramos, N.; Flores, W. et al.
System: The UNT Digital Library
High Energy Polarized Electron Beams (open access)

High Energy Polarized Electron Beams

In nearly all high energy electron storage rings the effect of beam polarization by synchrotron radiation has been measured. The buildup time for polarization in storage rings is of the order of 10{sup 6} to 10{sup 7} revolutions; the spins must remain aligned over this time in order to avoid depolarization. Even extremely small spin deviations per revolution can add up and cause depolarization. The injection and acceleration of polarized electrons in linacs is much easier. Although some improvements are still necessary, reliable polarized electron sources with sufficiently high intensity and polarization are available. With the linac-type machines SLC at Stanford and CEBAF in Virginia, experiments with polarized electrons will be possible.
Date: May 1, 1987
Creator: Rossmanith, Robert
System: The UNT Digital Library
Human somatic, germinal and heritable mutagenicity (open access)

Human somatic, germinal and heritable mutagenicity

This report deals with the general process of variant formation rather than with the consequences of a specific variant being present. It focusses on mutational mechanisms, mutagens, and the method for detecting de novo mutants and estimating mutation rate. It is to human genetics much like disease causation and prevention medicine are to medicine as a whole. The word ''mutagenicity'' is used in the title and throughout the text to connote the causation of all classes of genetic damage. Mutagenicity and the corresponding words mutation, mutagen and mutagenesis can have multiple meaning, sometimes relating to gene mutation, sometimes to heritable mutation, and somtimes to all types of genetic damage. 38 refs., 1 tab.
Date: May 1, 1987
Creator: Mendelsohn, M.L.
System: The UNT Digital Library
Improving Hatchery Effectiveness as Related to Smoltification: Proceedings of a Workshop held at Kah-Nee-Tah Lodge, Warm Springs, Oregon, May 20-23, 1985. (open access)

Improving Hatchery Effectiveness as Related to Smoltification: Proceedings of a Workshop held at Kah-Nee-Tah Lodge, Warm Springs, Oregon, May 20-23, 1985.

The Bonneville Power Administration (BPA) intends to develop a smoltification research effort that would have broad support among the interested parties. BPA sponsored this workshop on smoltification and related research to gather leading technical experts in the field in smoltification, permit them to exchange information about the state of the art of smoltification research, and allow them to identify and rank high-priority projects. This document includes keynote speeches, technical papers, and other sessions that summarize both what is known and what information is needed.
Date: May 1, 1987
Creator: Bouck, Gerald R.
System: The UNT Digital Library
Inflation in the Universe (open access)

Inflation in the Universe

The hot big bang cosmology, or the standard cosmology as it is appropriately known, is a highly successful model, providing a reliable and tested accounting of the Universe from 0.01 sec after the bang until today, some 15 Gyr later. However, very special initial data seem to be required in order to account for the observed smoothness and flatness of our Hubble volume and for the existence of the small primeval density inhomogeneities required for the formation of structure in the Universe. Inflation offers a means of accounting for these special initial data, which is based upon physics at sub-planck energy scales (<< m/sub pl/ approx. = 10/sup 19/ GeV) and is motivated by contemporary ideas in particle theory. Here I review the status of the 'Inflationary Paradigm'. At present essentially all inflationary models involve a very weakly-coupled (quantified by the presence of a dimensionless parameter of order 10/sup -12/ or so) scalar field which is displaced from the minimum of its potential. Regions of the Universe where the scalar field is initially displaced from its minimum undergo inflation as the scalar field relaxes, resulting in a Universe today which resembles ours in regions much larger than our present Hubble …
Date: May 1, 1987
Creator: Turner, M. S.
System: The UNT Digital Library
The influence of N-ion irradiation on superconducting TiN (open access)

The influence of N-ion irradiation on superconducting TiN

The influence of disorder on the properties of the B1 phase superconductive compound titanium nitride has been investigated. Following synthesis and characterization of thin films of TiN, the materials were disordered progressively and uniformly by irradiation with nitrogen ions. The superconducting transition temperature T/sub c/ decreased and the low temperature electrical resistivity rho increased as lattice damage was introduced. The dependence of both T/sub c/ and rho on N-ion fluence phi could be described by exponentially saturating functions of phi with similar rate constants. These constants correspond to characteristic damage energy densities of 14 and 12 eV/atom, respectively.
Date: May 1, 1987
Creator: Thompson, J. R.; Ellis, J. T.; Christen, D. K.; Sekula, S. T.; Lewis, J. D. & Williams, J. M.
System: The UNT Digital Library